Pascal's Triangle Generator in Python
$begingroup$
So I've been working on a generator for Pascal's triangle in Python. Now, I wouldn't call myself a Python god, so my program is a lot longer than the very confusing ones on the internet. It's more of a logical approach to creating the triangle.
Here's the program:
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
def pascal_next(lst):
return list(chunk_adder(double_chunker(lst)))
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
A simple go-through of how it works:
double_chunker()
splits up a row of Pascal's triangle into the pairs of numbers you would use when adding up to determine the numbers in the next row. This algorithm is little jerry-rigged - I had to add some special exceptions for some numbers on the end of the row to make it work properly.chunk_adder()
adds together a list of chunks generated bydouble_chunker
to determine the next row in the Pascal sequence.pascal_next()
combines bothdouble_chunker()
andchunk_adder()
to, when given one row in Pascal's triangle, determine the next row in the triangle.pascal_triangle()
iteratively creates rows of Pascal's triangle usingpascal_next()
.
So, here are some of my questions:
Is there anything in my program that seems redundant, repetitive, or can be shortened?
Is there any better code practices I should be employing and am not?
And obviously, as always, feel free to provide any other feedback you may have. Thanks in advance!
python
$endgroup$
add a comment |
$begingroup$
So I've been working on a generator for Pascal's triangle in Python. Now, I wouldn't call myself a Python god, so my program is a lot longer than the very confusing ones on the internet. It's more of a logical approach to creating the triangle.
Here's the program:
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
def pascal_next(lst):
return list(chunk_adder(double_chunker(lst)))
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
A simple go-through of how it works:
double_chunker()
splits up a row of Pascal's triangle into the pairs of numbers you would use when adding up to determine the numbers in the next row. This algorithm is little jerry-rigged - I had to add some special exceptions for some numbers on the end of the row to make it work properly.chunk_adder()
adds together a list of chunks generated bydouble_chunker
to determine the next row in the Pascal sequence.pascal_next()
combines bothdouble_chunker()
andchunk_adder()
to, when given one row in Pascal's triangle, determine the next row in the triangle.pascal_triangle()
iteratively creates rows of Pascal's triangle usingpascal_next()
.
So, here are some of my questions:
Is there anything in my program that seems redundant, repetitive, or can be shortened?
Is there any better code practices I should be employing and am not?
And obviously, as always, feel free to provide any other feedback you may have. Thanks in advance!
python
$endgroup$
add a comment |
$begingroup$
So I've been working on a generator for Pascal's triangle in Python. Now, I wouldn't call myself a Python god, so my program is a lot longer than the very confusing ones on the internet. It's more of a logical approach to creating the triangle.
Here's the program:
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
def pascal_next(lst):
return list(chunk_adder(double_chunker(lst)))
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
A simple go-through of how it works:
double_chunker()
splits up a row of Pascal's triangle into the pairs of numbers you would use when adding up to determine the numbers in the next row. This algorithm is little jerry-rigged - I had to add some special exceptions for some numbers on the end of the row to make it work properly.chunk_adder()
adds together a list of chunks generated bydouble_chunker
to determine the next row in the Pascal sequence.pascal_next()
combines bothdouble_chunker()
andchunk_adder()
to, when given one row in Pascal's triangle, determine the next row in the triangle.pascal_triangle()
iteratively creates rows of Pascal's triangle usingpascal_next()
.
So, here are some of my questions:
Is there anything in my program that seems redundant, repetitive, or can be shortened?
Is there any better code practices I should be employing and am not?
And obviously, as always, feel free to provide any other feedback you may have. Thanks in advance!
python
$endgroup$
So I've been working on a generator for Pascal's triangle in Python. Now, I wouldn't call myself a Python god, so my program is a lot longer than the very confusing ones on the internet. It's more of a logical approach to creating the triangle.
Here's the program:
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
def pascal_next(lst):
return list(chunk_adder(double_chunker(lst)))
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
A simple go-through of how it works:
double_chunker()
splits up a row of Pascal's triangle into the pairs of numbers you would use when adding up to determine the numbers in the next row. This algorithm is little jerry-rigged - I had to add some special exceptions for some numbers on the end of the row to make it work properly.chunk_adder()
adds together a list of chunks generated bydouble_chunker
to determine the next row in the Pascal sequence.pascal_next()
combines bothdouble_chunker()
andchunk_adder()
to, when given one row in Pascal's triangle, determine the next row in the triangle.pascal_triangle()
iteratively creates rows of Pascal's triangle usingpascal_next()
.
So, here are some of my questions:
Is there anything in my program that seems redundant, repetitive, or can be shortened?
Is there any better code practices I should be employing and am not?
And obviously, as always, feel free to provide any other feedback you may have. Thanks in advance!
python
python
asked 3 hours ago
connectyourchargerconnectyourcharger
1586
1586
add a comment |
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4 Answers
4
active
oldest
votes
$begingroup$
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
sum
can happilly consume iterable of size 1, it can even consume iterable of size 0:
>>> sum([1])
1
>>> sum()
0
So you can simplify it to:
def chunck_adder(iterable):
for element in iterable:
yield sum(element)
Which is simply
def chunck_adder(iterable):
yield from map(sum, iterable)
So you could simplify pascal_next
instead:
def pascal_next(lst):
return list(map(sum, double_chunker(lst)))
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
The intent is pretty much the same than the pairwise
recipe from itertools
. Except you want to yield the first and last element as well.
Here you have two possibilities:
either yield them manually:
import itertools
def double_chunker(lst):
if not lst:
return
a, b = itertools.tee(lst)
next(b, None)
yield [lst[0]]
yield from zip(a, b)
yield [lst[-1]]
But this forces the argument to be a list, or at least to know if its empty and to implement
__getitem__
.
or add boundary values to your input so
pairwise
can work properly:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
Which I recommend because it happily consume any iterable.
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
Instead of relying on the list being constructed, I would explicitly store the current row. I would also turn this into an infinite generator because it really is and maybe provide an helper function for convenience:
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
Full code:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
def pascal_next(iterable):
return list(map(sum, double_chuncker(iterable)))
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
if __name__ == '__main__':
# Testing
for row in pascal_triangle():
print(row, end='')
if (input()):
break
$endgroup$
add a comment |
$begingroup$
Names
I am not fully convinced by the different function names but I have nothing better to suggest for the time being.
Style
Python has a Style Guide called PEP 8. It is an interesting read. The most significant impact for your code would be to use 4 spaces for each indentation level instead of 2.
Simplify double_chunker
In double_chunker
, the following condition is never true:
elif i == leng:
yield [lst[-1]]
Also, you don't need to handle explicitly the case:
elif i == 1:
yield [lst[0], lst[1]]
as it is just a particular case for [lst[i-1], lst[i]]
with i == 1
.
Simplify chunk_adder
In chunk_adder
, instead of:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
We can write:
yield sum(i)
Then, we could rewrite the function using generator expressions:
def chunk_adder(lst):
return (sum(i) for i in lst)
Then, it looks like the function is not really needed. We could write:
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
At this stage, we have:
def double_chunker(lst):
for i in range(len(lst)):
if i == 0:
yield [lst[0]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
print(pascal_triangle(8))
More simplification in double_chunker
We could handle the case i == 0
before the loop rather than inside the loop. That could lead to a slightly different behavior when the input is an empty list but that case is not handled properly anyway (exception thrown).
def double_chunker(lst):
yield [lst[0]]
for i in range(1, len(lst)):
yield [lst[i-1], lst[i]]
yield [lst[-1]]
Then, it becomes obvious what we want to do: we want to iterate over all pairs of consecutive items in a list which is a problem common enough to find various solutions to it.
$endgroup$
add a comment |
$begingroup$
Is there any better code practices I should be employing and am not?
- The first thing that caught my attention is the missing tests
You should implement a few test cases to ensure that after changes the program does still work as intended
Both the unittest module or doctest are good Python modules for testing, I have used the unittest
as an example
class PascalTriangleTest(unittest.TestCase):
def test_triangle_0(self):
self.assertEqual(
pascal_triangle(0),
[[1]]
)
def test_triangle_1(self):
self.assertEqual(
pascal_triangle(1),
[[1], [1, 1]]
)
def test_triangle_2(self):
self.assertEqual(
pascal_triangle(2),
[[1], [1, 1], [1, 2, 1]]
)
def test_triangle_3(self):
self.assertEqual(
pascal_triangle(3),
[[1], [1, 1], [1, 2, 1], [1, 3, 3, 1]]
)
if __name__ == '__main__':
unittest.main()
- The second one would be the missing docstrings
The comments below your code would be a good start to make the docstring for each function.
See PEP257, for docstring conventions
$endgroup$
add a comment |
$begingroup$
Is there anything in my program that seems redundant, repetitive, or can be shortened?
The 22 lines of double_chunker
, chunk_adder
, and pascal_next
can be shortened to
def pascal_next(lst):
return [left + right for (left, right) in zip(lst + [0], [0] + lst)]
$endgroup$
$begingroup$
Orreturn [sum(pair) for pair in zip(lst + [0], [0] + lst)]
to make use of the built insum
$endgroup$
– Ludisposed
3 mins ago
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
sum
can happilly consume iterable of size 1, it can even consume iterable of size 0:
>>> sum([1])
1
>>> sum()
0
So you can simplify it to:
def chunck_adder(iterable):
for element in iterable:
yield sum(element)
Which is simply
def chunck_adder(iterable):
yield from map(sum, iterable)
So you could simplify pascal_next
instead:
def pascal_next(lst):
return list(map(sum, double_chunker(lst)))
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
The intent is pretty much the same than the pairwise
recipe from itertools
. Except you want to yield the first and last element as well.
Here you have two possibilities:
either yield them manually:
import itertools
def double_chunker(lst):
if not lst:
return
a, b = itertools.tee(lst)
next(b, None)
yield [lst[0]]
yield from zip(a, b)
yield [lst[-1]]
But this forces the argument to be a list, or at least to know if its empty and to implement
__getitem__
.
or add boundary values to your input so
pairwise
can work properly:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
Which I recommend because it happily consume any iterable.
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
Instead of relying on the list being constructed, I would explicitly store the current row. I would also turn this into an infinite generator because it really is and maybe provide an helper function for convenience:
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
Full code:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
def pascal_next(iterable):
return list(map(sum, double_chuncker(iterable)))
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
if __name__ == '__main__':
# Testing
for row in pascal_triangle():
print(row, end='')
if (input()):
break
$endgroup$
add a comment |
$begingroup$
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
sum
can happilly consume iterable of size 1, it can even consume iterable of size 0:
>>> sum([1])
1
>>> sum()
0
So you can simplify it to:
def chunck_adder(iterable):
for element in iterable:
yield sum(element)
Which is simply
def chunck_adder(iterable):
yield from map(sum, iterable)
So you could simplify pascal_next
instead:
def pascal_next(lst):
return list(map(sum, double_chunker(lst)))
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
The intent is pretty much the same than the pairwise
recipe from itertools
. Except you want to yield the first and last element as well.
Here you have two possibilities:
either yield them manually:
import itertools
def double_chunker(lst):
if not lst:
return
a, b = itertools.tee(lst)
next(b, None)
yield [lst[0]]
yield from zip(a, b)
yield [lst[-1]]
But this forces the argument to be a list, or at least to know if its empty and to implement
__getitem__
.
or add boundary values to your input so
pairwise
can work properly:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
Which I recommend because it happily consume any iterable.
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
Instead of relying on the list being constructed, I would explicitly store the current row. I would also turn this into an infinite generator because it really is and maybe provide an helper function for convenience:
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
Full code:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
def pascal_next(iterable):
return list(map(sum, double_chuncker(iterable)))
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
if __name__ == '__main__':
# Testing
for row in pascal_triangle():
print(row, end='')
if (input()):
break
$endgroup$
add a comment |
$begingroup$
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
sum
can happilly consume iterable of size 1, it can even consume iterable of size 0:
>>> sum([1])
1
>>> sum()
0
So you can simplify it to:
def chunck_adder(iterable):
for element in iterable:
yield sum(element)
Which is simply
def chunck_adder(iterable):
yield from map(sum, iterable)
So you could simplify pascal_next
instead:
def pascal_next(lst):
return list(map(sum, double_chunker(lst)))
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
The intent is pretty much the same than the pairwise
recipe from itertools
. Except you want to yield the first and last element as well.
Here you have two possibilities:
either yield them manually:
import itertools
def double_chunker(lst):
if not lst:
return
a, b = itertools.tee(lst)
next(b, None)
yield [lst[0]]
yield from zip(a, b)
yield [lst[-1]]
But this forces the argument to be a list, or at least to know if its empty and to implement
__getitem__
.
or add boundary values to your input so
pairwise
can work properly:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
Which I recommend because it happily consume any iterable.
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
Instead of relying on the list being constructed, I would explicitly store the current row. I would also turn this into an infinite generator because it really is and maybe provide an helper function for convenience:
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
Full code:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
def pascal_next(iterable):
return list(map(sum, double_chuncker(iterable)))
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
if __name__ == '__main__':
# Testing
for row in pascal_triangle():
print(row, end='')
if (input()):
break
$endgroup$
def chunk_adder(lst):
for i in lst:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
sum
can happilly consume iterable of size 1, it can even consume iterable of size 0:
>>> sum([1])
1
>>> sum()
0
So you can simplify it to:
def chunck_adder(iterable):
for element in iterable:
yield sum(element)
Which is simply
def chunck_adder(iterable):
yield from map(sum, iterable)
So you could simplify pascal_next
instead:
def pascal_next(lst):
return list(map(sum, double_chunker(lst)))
def double_chunker(lst):
leng = len(lst)
for i in range(leng):
if i == 0:
yield [lst[0]]
elif i == 1:
yield [lst[0], lst[1]]
elif i == leng:
yield [lst[-1]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
The intent is pretty much the same than the pairwise
recipe from itertools
. Except you want to yield the first and last element as well.
Here you have two possibilities:
either yield them manually:
import itertools
def double_chunker(lst):
if not lst:
return
a, b = itertools.tee(lst)
next(b, None)
yield [lst[0]]
yield from zip(a, b)
yield [lst[-1]]
But this forces the argument to be a list, or at least to know if its empty and to implement
__getitem__
.
or add boundary values to your input so
pairwise
can work properly:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
Which I recommend because it happily consume any iterable.
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
Instead of relying on the list being constructed, I would explicitly store the current row. I would also turn this into an infinite generator because it really is and maybe provide an helper function for convenience:
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
Full code:
import itertools
def pairwise(iterable):
a, b = itertools.tee(iterable)
next(b, None)
return zip(a, b)
def double_chuncker(iterable):
extended = itertools.chain([0], iterable, [0])
return pairwise(extended)
def pascal_next(iterable):
return list(map(sum, double_chuncker(iterable)))
def pascal_triangle():
row = [1]
while True:
yield row
row = pascal_next(row)
def pascal_triangle_up_to(n):
return list(itertools.islice(pascal_triangle(), n))
if __name__ == '__main__':
# Testing
for row in pascal_triangle():
print(row, end='')
if (input()):
break
edited 1 hour ago
answered 1 hour ago
Mathias EttingerMathias Ettinger
24k33182
24k33182
add a comment |
add a comment |
$begingroup$
Names
I am not fully convinced by the different function names but I have nothing better to suggest for the time being.
Style
Python has a Style Guide called PEP 8. It is an interesting read. The most significant impact for your code would be to use 4 spaces for each indentation level instead of 2.
Simplify double_chunker
In double_chunker
, the following condition is never true:
elif i == leng:
yield [lst[-1]]
Also, you don't need to handle explicitly the case:
elif i == 1:
yield [lst[0], lst[1]]
as it is just a particular case for [lst[i-1], lst[i]]
with i == 1
.
Simplify chunk_adder
In chunk_adder
, instead of:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
We can write:
yield sum(i)
Then, we could rewrite the function using generator expressions:
def chunk_adder(lst):
return (sum(i) for i in lst)
Then, it looks like the function is not really needed. We could write:
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
At this stage, we have:
def double_chunker(lst):
for i in range(len(lst)):
if i == 0:
yield [lst[0]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
print(pascal_triangle(8))
More simplification in double_chunker
We could handle the case i == 0
before the loop rather than inside the loop. That could lead to a slightly different behavior when the input is an empty list but that case is not handled properly anyway (exception thrown).
def double_chunker(lst):
yield [lst[0]]
for i in range(1, len(lst)):
yield [lst[i-1], lst[i]]
yield [lst[-1]]
Then, it becomes obvious what we want to do: we want to iterate over all pairs of consecutive items in a list which is a problem common enough to find various solutions to it.
$endgroup$
add a comment |
$begingroup$
Names
I am not fully convinced by the different function names but I have nothing better to suggest for the time being.
Style
Python has a Style Guide called PEP 8. It is an interesting read. The most significant impact for your code would be to use 4 spaces for each indentation level instead of 2.
Simplify double_chunker
In double_chunker
, the following condition is never true:
elif i == leng:
yield [lst[-1]]
Also, you don't need to handle explicitly the case:
elif i == 1:
yield [lst[0], lst[1]]
as it is just a particular case for [lst[i-1], lst[i]]
with i == 1
.
Simplify chunk_adder
In chunk_adder
, instead of:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
We can write:
yield sum(i)
Then, we could rewrite the function using generator expressions:
def chunk_adder(lst):
return (sum(i) for i in lst)
Then, it looks like the function is not really needed. We could write:
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
At this stage, we have:
def double_chunker(lst):
for i in range(len(lst)):
if i == 0:
yield [lst[0]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
print(pascal_triangle(8))
More simplification in double_chunker
We could handle the case i == 0
before the loop rather than inside the loop. That could lead to a slightly different behavior when the input is an empty list but that case is not handled properly anyway (exception thrown).
def double_chunker(lst):
yield [lst[0]]
for i in range(1, len(lst)):
yield [lst[i-1], lst[i]]
yield [lst[-1]]
Then, it becomes obvious what we want to do: we want to iterate over all pairs of consecutive items in a list which is a problem common enough to find various solutions to it.
$endgroup$
add a comment |
$begingroup$
Names
I am not fully convinced by the different function names but I have nothing better to suggest for the time being.
Style
Python has a Style Guide called PEP 8. It is an interesting read. The most significant impact for your code would be to use 4 spaces for each indentation level instead of 2.
Simplify double_chunker
In double_chunker
, the following condition is never true:
elif i == leng:
yield [lst[-1]]
Also, you don't need to handle explicitly the case:
elif i == 1:
yield [lst[0], lst[1]]
as it is just a particular case for [lst[i-1], lst[i]]
with i == 1
.
Simplify chunk_adder
In chunk_adder
, instead of:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
We can write:
yield sum(i)
Then, we could rewrite the function using generator expressions:
def chunk_adder(lst):
return (sum(i) for i in lst)
Then, it looks like the function is not really needed. We could write:
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
At this stage, we have:
def double_chunker(lst):
for i in range(len(lst)):
if i == 0:
yield [lst[0]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
print(pascal_triangle(8))
More simplification in double_chunker
We could handle the case i == 0
before the loop rather than inside the loop. That could lead to a slightly different behavior when the input is an empty list but that case is not handled properly anyway (exception thrown).
def double_chunker(lst):
yield [lst[0]]
for i in range(1, len(lst)):
yield [lst[i-1], lst[i]]
yield [lst[-1]]
Then, it becomes obvious what we want to do: we want to iterate over all pairs of consecutive items in a list which is a problem common enough to find various solutions to it.
$endgroup$
Names
I am not fully convinced by the different function names but I have nothing better to suggest for the time being.
Style
Python has a Style Guide called PEP 8. It is an interesting read. The most significant impact for your code would be to use 4 spaces for each indentation level instead of 2.
Simplify double_chunker
In double_chunker
, the following condition is never true:
elif i == leng:
yield [lst[-1]]
Also, you don't need to handle explicitly the case:
elif i == 1:
yield [lst[0], lst[1]]
as it is just a particular case for [lst[i-1], lst[i]]
with i == 1
.
Simplify chunk_adder
In chunk_adder
, instead of:
if len(i) == 1:
yield i[0]
else:
yield sum(i)
We can write:
yield sum(i)
Then, we could rewrite the function using generator expressions:
def chunk_adder(lst):
return (sum(i) for i in lst)
Then, it looks like the function is not really needed. We could write:
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
At this stage, we have:
def double_chunker(lst):
for i in range(len(lst)):
if i == 0:
yield [lst[0]]
else:
yield [lst[i-1], lst[i]]
yield [lst[-1]]
def pascal_next(lst):
return [sum(i) for i in double_chunker(lst)]
def pascal_triangle(rows):
end = [[1]]
for i in range(rows):
end.append(pascal_next(end[-1]))
return end
print(pascal_triangle(8))
More simplification in double_chunker
We could handle the case i == 0
before the loop rather than inside the loop. That could lead to a slightly different behavior when the input is an empty list but that case is not handled properly anyway (exception thrown).
def double_chunker(lst):
yield [lst[0]]
for i in range(1, len(lst)):
yield [lst[i-1], lst[i]]
yield [lst[-1]]
Then, it becomes obvious what we want to do: we want to iterate over all pairs of consecutive items in a list which is a problem common enough to find various solutions to it.
answered 1 hour ago
JosayJosay
25.7k14087
25.7k14087
add a comment |
add a comment |
$begingroup$
Is there any better code practices I should be employing and am not?
- The first thing that caught my attention is the missing tests
You should implement a few test cases to ensure that after changes the program does still work as intended
Both the unittest module or doctest are good Python modules for testing, I have used the unittest
as an example
class PascalTriangleTest(unittest.TestCase):
def test_triangle_0(self):
self.assertEqual(
pascal_triangle(0),
[[1]]
)
def test_triangle_1(self):
self.assertEqual(
pascal_triangle(1),
[[1], [1, 1]]
)
def test_triangle_2(self):
self.assertEqual(
pascal_triangle(2),
[[1], [1, 1], [1, 2, 1]]
)
def test_triangle_3(self):
self.assertEqual(
pascal_triangle(3),
[[1], [1, 1], [1, 2, 1], [1, 3, 3, 1]]
)
if __name__ == '__main__':
unittest.main()
- The second one would be the missing docstrings
The comments below your code would be a good start to make the docstring for each function.
See PEP257, for docstring conventions
$endgroup$
add a comment |
$begingroup$
Is there any better code practices I should be employing and am not?
- The first thing that caught my attention is the missing tests
You should implement a few test cases to ensure that after changes the program does still work as intended
Both the unittest module or doctest are good Python modules for testing, I have used the unittest
as an example
class PascalTriangleTest(unittest.TestCase):
def test_triangle_0(self):
self.assertEqual(
pascal_triangle(0),
[[1]]
)
def test_triangle_1(self):
self.assertEqual(
pascal_triangle(1),
[[1], [1, 1]]
)
def test_triangle_2(self):
self.assertEqual(
pascal_triangle(2),
[[1], [1, 1], [1, 2, 1]]
)
def test_triangle_3(self):
self.assertEqual(
pascal_triangle(3),
[[1], [1, 1], [1, 2, 1], [1, 3, 3, 1]]
)
if __name__ == '__main__':
unittest.main()
- The second one would be the missing docstrings
The comments below your code would be a good start to make the docstring for each function.
See PEP257, for docstring conventions
$endgroup$
add a comment |
$begingroup$
Is there any better code practices I should be employing and am not?
- The first thing that caught my attention is the missing tests
You should implement a few test cases to ensure that after changes the program does still work as intended
Both the unittest module or doctest are good Python modules for testing, I have used the unittest
as an example
class PascalTriangleTest(unittest.TestCase):
def test_triangle_0(self):
self.assertEqual(
pascal_triangle(0),
[[1]]
)
def test_triangle_1(self):
self.assertEqual(
pascal_triangle(1),
[[1], [1, 1]]
)
def test_triangle_2(self):
self.assertEqual(
pascal_triangle(2),
[[1], [1, 1], [1, 2, 1]]
)
def test_triangle_3(self):
self.assertEqual(
pascal_triangle(3),
[[1], [1, 1], [1, 2, 1], [1, 3, 3, 1]]
)
if __name__ == '__main__':
unittest.main()
- The second one would be the missing docstrings
The comments below your code would be a good start to make the docstring for each function.
See PEP257, for docstring conventions
$endgroup$
Is there any better code practices I should be employing and am not?
- The first thing that caught my attention is the missing tests
You should implement a few test cases to ensure that after changes the program does still work as intended
Both the unittest module or doctest are good Python modules for testing, I have used the unittest
as an example
class PascalTriangleTest(unittest.TestCase):
def test_triangle_0(self):
self.assertEqual(
pascal_triangle(0),
[[1]]
)
def test_triangle_1(self):
self.assertEqual(
pascal_triangle(1),
[[1], [1, 1]]
)
def test_triangle_2(self):
self.assertEqual(
pascal_triangle(2),
[[1], [1, 1], [1, 2, 1]]
)
def test_triangle_3(self):
self.assertEqual(
pascal_triangle(3),
[[1], [1, 1], [1, 2, 1], [1, 3, 3, 1]]
)
if __name__ == '__main__':
unittest.main()
- The second one would be the missing docstrings
The comments below your code would be a good start to make the docstring for each function.
See PEP257, for docstring conventions
answered 31 mins ago
LudisposedLudisposed
7,31421959
7,31421959
add a comment |
add a comment |
$begingroup$
Is there anything in my program that seems redundant, repetitive, or can be shortened?
The 22 lines of double_chunker
, chunk_adder
, and pascal_next
can be shortened to
def pascal_next(lst):
return [left + right for (left, right) in zip(lst + [0], [0] + lst)]
$endgroup$
$begingroup$
Orreturn [sum(pair) for pair in zip(lst + [0], [0] + lst)]
to make use of the built insum
$endgroup$
– Ludisposed
3 mins ago
add a comment |
$begingroup$
Is there anything in my program that seems redundant, repetitive, or can be shortened?
The 22 lines of double_chunker
, chunk_adder
, and pascal_next
can be shortened to
def pascal_next(lst):
return [left + right for (left, right) in zip(lst + [0], [0] + lst)]
$endgroup$
$begingroup$
Orreturn [sum(pair) for pair in zip(lst + [0], [0] + lst)]
to make use of the built insum
$endgroup$
– Ludisposed
3 mins ago
add a comment |
$begingroup$
Is there anything in my program that seems redundant, repetitive, or can be shortened?
The 22 lines of double_chunker
, chunk_adder
, and pascal_next
can be shortened to
def pascal_next(lst):
return [left + right for (left, right) in zip(lst + [0], [0] + lst)]
$endgroup$
Is there anything in my program that seems redundant, repetitive, or can be shortened?
The 22 lines of double_chunker
, chunk_adder
, and pascal_next
can be shortened to
def pascal_next(lst):
return [left + right for (left, right) in zip(lst + [0], [0] + lst)]
answered 7 mins ago
Peter TaylorPeter Taylor
15.9k2759
15.9k2759
$begingroup$
Orreturn [sum(pair) for pair in zip(lst + [0], [0] + lst)]
to make use of the built insum
$endgroup$
– Ludisposed
3 mins ago
add a comment |
$begingroup$
Orreturn [sum(pair) for pair in zip(lst + [0], [0] + lst)]
to make use of the built insum
$endgroup$
– Ludisposed
3 mins ago
$begingroup$
Or
return [sum(pair) for pair in zip(lst + [0], [0] + lst)]
to make use of the built in sum
$endgroup$
– Ludisposed
3 mins ago
$begingroup$
Or
return [sum(pair) for pair in zip(lst + [0], [0] + lst)]
to make use of the built in sum
$endgroup$
– Ludisposed
3 mins ago
add a comment |
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