Intersection between list and first element of list of lists

enumerate, intersection, list, python

Solution

Your output is easily accomplished using a list comprehension:

wl=['A', 'Aani', 'Aaron', 'Aaronic', 'Aaronical', 'Aaronite', 'Aaronitic', 'Aaru', 'Ab', 'Ababdeh']
wlc=[['A','0'], ['Aaronic','1'], ['Key','2'], ['Aaronical','3'], ['Aaronite','4'], ['Yes','5']]

print [[word, i] for word,i in wlc if word in wl]    
# [['A', '0'], ['Aaronic', '1'], ['Aaronical', '3'], ['Aaronite', '4']]

Alternative LC:

print [li for li in wlc if li[0] in wl]

If you want a looping structure:

wlf = []
for word, i in wlc:
    if word in wl:
        wlf.append([word,i])

print wlf       
# [['A', '0'], ['Aaronic', '1'], ['Aaronical', '3'], ['Aaronite', '4']]

Python sequences usually don't need to be enumerated to just deal with the objects in the sequence. You usually only need to use `enumerate` if there is something about the index or order that is 'data' in addition to the sequence itself.

Here you are taking each element in `wordlist_compound` and testing membership of the word in `wordlist`. No need for enumeration. You also greatly simplify the task if you reverse the loops; loop over `wordlist_compound` rather than looping over `wordlist` in the outer loop as you have it. Your output is a filter of the elements in `wordlist_compound`; which, of course, means you can use `filter` too:

print filter(lambda li: li[0] in wl, wlc)
# [['A', '0'], ['Aaronic', '1'], ['Aaronical', '3'], ['Aaronite', '4']]

Cheers.

Problem

I have two lists: ``` wordlist = ['A', 'Aani', 'Aaron', 'Aaronic', 'Aaronical', 'Aaronite', 'Aaronitic', 'Aaru', 'Ab', 'Ababdeh'] ``` and ``` wordlist_compound = [['A','0'], ['Aaronic','1'], ['Key','2'], ['Aaronical','3'], ['Aaronite','4'], ['Yes','5']] ``` I would like to take the intersection of the two words and make a list that contains the word, number combination number in a third list, wordlist_final, so that wordlist_final looks like: ``` [['A','0'], ['Aaronic','1'], ['Aaronical','3'], ['Aaronite','4']] ``` My current code looks like: ``` wordlist_final = [] for index, word in enumerate(wordlist): for word_comp in wordlist_compound: if word[index] == wordlist_compound[index][0]: wordlist_final.append(wordlist_compound[index]) ``` But I'm getting a "string index out of range error"

Original source