How to apply a function or command to every row of a list?

Question

I have a list of items in a string with 2 columns and dozens of rows. I want to filter out every item from one of the columns. I think I can do this by applying the .split command on each row but if there's any better way to do this that doesn't involve regex I'd like to know.

Edit: I'm trying to do this with a list of names like:

"""Roy      Theresa     
Vincent     Diana   
Ralph       Natalie     
Eugene      Brittany""" etc.

When I use:

head, sep, tail = nameList.partition(' ')
print(head)

It only returns the first name in the list. I want to apply that code to every line of the string so I can get the first name off every line instead of just the first one in the whole list.

Answer 1

If you have a direct list like:

a = ["Roy Theresa","Vincent Diana","Ralph Natalie","Eugene Brittany"]

then all you have to do is :

for i in a:
    print(i.split(" ")[0])

to get the first world from each element of the list.

But if you have a String like :

b = """Roy      Theresa     
Vincent     Diana   
Ralph       Natalie     
Eugene      Brittany"""

First you must divide it into different names using splitlines() and repeat the top step once you get a list of names, like this:

new_list = b.splitlines()
for i in new_list:
    print(i.split(" ")[0])

Your output will be:

Roy
Vincent
Ralph
Eugene