Why this does not work?
[ print("%d03" % a) for a in range(1,99)]
File "<stdin>", line 1
[ print("%d03" % a) for a in range(1,99)]
^
SyntaxError: invalid syntax
but
print("%03d" % a)
098
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4 Answers
In Python 2.x, print is a statement, so it cannot appear as part of an expression. In Python 3.x, the list comprehension would be syntactically correct because print was turned into a function, though a bit pointless since print() always returns None.
In any case, this is the right way to do it:
for a in range(1,99):
print("%d03" % a)
Comments
I'm not sure why you can't use print in a list comprehension, but you can work around it:
In: print ["%03d" % a for a in range(1,10)]
['001', '002', '003', '004', '005', '006', '007', '008', '009']
Comments
print('\n'.join(['%d03' % i for i in range(1,99)]))
print doesn't return anything so you can't use it in an expression.
Comments
This is because print() is a function that prints the arguments, but does not return them. Good news is that you don't need print() for formatting.
What you (probably) are looking for is:
["%03d" % a for a in range(1,99)]
or using the built in function format():
[format(a, "03d") for a in range(1,99)]
If you indeed want to print() the numbers, then don't use list comprehension, but just a simple for loop:
for _ in range(99): print("%03d" % _)
