Getting an error with this code (SyntaxError: invalid syntax)
score = [a*a in range(1, 100) if (a*a)%2 is 0 and str(a*a)[-1] is '0']
print(score)
Result:
SyntaxError: invalid syntax
but same code working fine when i use it without list comprehension method.
score = []
for a in range(1,100):
if (a*a)%2 is 0 and str(a*a)[-1] is '0':
score.append(a*a)
print(score)
result:
[100, 400, 900, 1600, 2500, 3600, 4900, 6400, 8100]
You are missing the for a
. Also, you should use ==
to test ints and strings for equality because is
checks object identity:
score = [a*a for a in range(1, 100) if (a*a) % 2 == 0 and str(a*a)[-1] == '0']
You could also shorten the == 0
to a bool
check and generally consider to use endswith
for more robust suffix checking:
score = [a*a for a in range(1, 100) if not (a*a) % 2 and str(a*a).endswith('0')]
See the docs on list comprehensions .
The problem is the yield part of the expression:
score = [ in range(1, 100) if (a*a)%2 is 0 and str(a*a)[-1] is '0']
You want to add a*a
to the list, so:
score = [ in range(1, 100) if (a*a)%2 is 0 and str(a*a)[-1] is '0']
But the code is very inelegantly. You use is
which is reference equality. Although most interpreters cache characters, and small integers, it is a bit risky to rely on it: the more assumptions that have to be satisfied for a program to work, the more can go wrong.
Furthermore you can detect whether a*a
will end with 0
, by checking (a*a)%10 == 0
. Since 10
is a multiple of 2
, we can even drop the first check then. We can check for an integer i
being zero with not i
(this is True
is i == 0
).
So a more safe and shorter solution is:
score = [a*a for a in range(1, 100) if ]
This then produces then:
>>> [a*a for a in range(1, 100) if not (a * a) % 10]
[100, 400, 900, 1600, 2500, 3600, 4900, 6400, 8100]
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