Generate list with one string followed by a number of None values

Question

I'm trying to generate this list:

["var",None,None,None,None,None]

What's the short way to do this? I thought

list_2=["var",None for cnt in range(5)]

would work but it just generates an error. My second attempt,

list_1=["var"].extend([None for cnt in range(5)])

wasn't exactly a success story either. Could anyone please help?

Thank you!

Answer 1

This can simply be done as

mylist = ["var"] + [None] * 5

The Reason,

["var"].extend([None for cnt in range(5)])

will not work, because extends changes the list in-place, but does not return the original list. You could have done

mylist = ["var"]
mylist.extend([None for cnt in range(5)])

Your second attempt

list_2=["var",None for cnt in range(5)]

is also not correct

1. Because its a generator expression without parenthesis.
2. Even if it would have worked, it would add what ever you get as the second item in the list

Answer 2

You can do it this way:

>>> list_1 = ["var"] + [None]*5
>>> list_1
['var', None, None, None, None, None]

Answer 3

Python 3.2

a=["var"]
_=[a.append(None)for v in range(5)] 

another way with extend:

a=["var"]
b=[None]*5
a.extend(b)