CODEWITHSUNDEEP
pythonstringlistconcatenation
mojbius
mojbius

Reputation: 95

Concatenating string to list iteratively

So I'm trying to concatenate a string to a list, but for some reason it only works for the very last values:

labels_and_sents = []
for l in labels:
    for s in sents:
        sl = [l] + s
    
 labels_and_sents.append(sl)

Input:

labels = ['1','2','3']
sents = [['hi hello'], ['i was there'], ['this is a sent']]

Output:

[['3', 'this is a sent']]

What i need is:

[['1', 'hi hello'],['2', 'i was there'],['3', 'this is a sent']]

Upvotes: 0

Views: 40

Answers (2)

Daweo
Daweo

Reputation: 36380

For me this looks like task for map, I would do

labels = ['1','2','3']
sents = [['hi hello'], ['i was there'], ['this is a sent']]
output = list(map(lambda x,y:[x]+y,labels,sents))
print(output)

Output:

[['1', 'hi hello'], ['2', 'i was there'], ['3', 'this is a sent']]

Explanation: for every pair of corresponding elements from labels and sents I pack first one into list and then concatenate with latter. This solution assumes len(labels)==len(sents) does hold True.

Upvotes: 2

akinul
akinul

Reputation: 11

If you only want to do it with loop then try following:

labels = ['1','2','3']
sents = [['hi hello'], ['i was there'], ['this is a sent']]
output = []

for i in range(len(labels)):
    output.append([ labels[i], sents[i][0] ])
print(output)

output:

[['1', 'hi hello'], ['2', 'i was there'], ['3', 'this is a sent']]

Upvotes: 1

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