Find the index of the second occurrence of a string inside a list

Question

This is my list and code:

x=[[\"hi hello\"], [\"this is other\"],[\"this\"],[\"something\"],[\"this\"],[\"last element\"]]
for line in x:
    y=x.index(line)         


        

Answer 1

You can get the second easily enough by using list slices. In the example below, we find the index of the first occurance and then find the index of the first occurance in the sub-list that begins just after the first occurance.

x=[["hi hello"], ["this is other"],["this"],["something"],["this"],["last element"]]
for line in x:
    first=x.index(line)
    second=x[first+1:].index(line)
    #code

Bare in mind that using list.index() will return a ValueError if the object isn't in the list. Thus you may want some exception handling around your inner loop.

So the final code will look somewhat closer to this:

x=[["hi hello"], ["this is other"],["this"],["something"],["this"],["last element"]]
for line in x:
    print lines
    try:
        first=x.index(line)
        second=x[first+1:].index(line)
    except:
        first,second=-1,-1
    print first,second
    #code