I have the following list:
ll = ['listA_5_val','listB_15_val','listC_25_val']
and I would like to create a new list based on this:
new_list = [5,15,25]
where we have extracted the number from each list. I can do this for a single element like this:
ll[0][6:-4]
How do I do this to entire list?
Using list comprehension:
>>> ll = ['listA_5_val','listB_15_val','listC_25_val']
>>> [int(x[6:-4]) for x in ll]
[5, 15, 25]
>>> [int(x.split('_')[1]) for x in ll]
[5, 15, 25]
Sure, with a list comprehension it can be done this way:
arr = [int(i[6:-4]) for i in ll]
And will result in: [5, 15, 25]
For each element, one of the better ways would be to use str.split to cut the element into three parts, and then convert the middle part to an integer:
int(element.split("_")[1])
To do this for every element, the most pythonic way would be to use list comprehensions:
new_list = [int(element.split("_")[1]) for element in ll]
if there is only one time digit in string:
import re
ll = ['listA_5_val','listB_15_val','listC_25_val']
[ re.findall('\d+',x)[0] for x in ll ]
