How to concatenate element-wise two lists in Python

I have two lists and I want to concatenate them element-wise. One of the list is subjected to string-formatting before concatenation.

For example :

a = [0, 1, 5, 6, 10, 11] 
b = ['asp1', 'asp1', 'asp1', 'asp1', 'asp2', 'asp2']

In this case, a is subjected to string-formatting. That is, new a or aa should be :

aa = [00, 01, 05, 06, 10, 11]

Final output should be :

c = ['asp100', 'asp101', 'asp105', 'asp106', 'asp210', 'asp211']

Can somebody please tell me how to do that?

Solution 1:

Use zip:

>>> ["{}{:02}".format(b_, a_) for a_, b_ in zip(a, b)]
['asp100', 'asp101', 'asp105', 'asp106', 'asp210', 'asp211']

Using zip

[m+str(n) for m,n in zip(b,a)]

output

['asp10', 'asp11', 'asp15', 'asp16', 'asp210', 'asp211']

Other solution (preferring printf formating style over .format() usage), it's also smaller:

>>> ["%s%02d" % t for t in zip(b, a)]
['asp100', 'asp101', 'asp105', 'asp106', 'asp210', 'asp211']

Than can be done elegantly with map and zip:

map(lambda (x,y): x+y, zip(list1, list2))

Example:

In [1]: map(lambda (x,y): x+y, zip([1,2,3,4],[4,5,6,7]))
Out[1]: [5, 7, 9, 11]