How can I get the nth element of String for list of list in python?

Question

I have my txt file something like this.

[0, "we break dance not hearts by Short Stack is my ringtone.... i LOVE that !!!.....\n"]
[1, "I want to write a . I think I will.\n"]
[2, "@va_stress broke my twitter..\n"]
[3, "\" &quot;Y must people insist on talking about stupid politics on the comments of a bubblegum pop . Sorry\n"]
[4, "aww great  &quot;Picture to burn&quot;\n"]

I have a some code which want to access the 2nd element of each array. When I use the code from Get the nth element from the inner list of a list of lists in Python It is giving each characters but not the entire string.

What could be the best way to make a loop for getting second element?

My code is something like this.

ALl the tweets are in the tweets[] list.

cluster = []
for idx, cls in enumerate(km.labels_):
    if cls == 1:
        # printing cluster 2 data.
        # print tweets from the tweets array. like the entire line. But I 
        # want to get the String here not the entire line.
        print tweets[idx]
        cluster.append(tweets[idx])

Here, idx element is used to get specific queries. so tweets[idx] will print specific queries from the text file but It is printing the entire line like [2, "@va_stress broke my twitter..\n"] and I want string element only.

Please show the code you have written so far. I also suggest that you read https://ericlippert.com/2014/03/05/how-to-debug-small-programs/ for some debugging tips. — Code-Apprentice, Apr 11 '18 at 15:11
The link you provided was for a list of lists. You just have a list. Getting the second element (index 1) is as simple as `l[1]`. — Robert Seaman, Apr 11 '18 at 15:11
Unless all this is inside a list itself, you can access every 2nd element with `myarray[1]`. If these lists are inside a list, you can do `myarray[ : , 1]` in which you select every index, then only the 2nd index of each index. — Antry, Apr 11 '18 at 15:13
print tweets[idx, 1] TypeError: list indices must be integers, not tuple — Viral Patel, Apr 11 '18 at 16:27

score 0 · Answer 1 · answered Apr 11 '18 at 15:13

0

I guess what you are wanting is the string from each list. I am assuming you already would have a list of list parameter with each list from your text file. hence you can apply this to get the values.

list_of_strings = filter(lambda x:x[1], list_of_lists)

answered Apr 11 '18 at 15:13

Kenstars

662
4
11

how does this go against `list_of_strings[:, 1]` ? – Antry Apr 11 '18 at 15:16
@Kenstars Can you please apply your suggestion to my code? Thank you – Viral Patel Apr 11 '18 at 15:25
@Antry I've personally not checked the processing time, I guess your way of doing it might work out faster. – Kenstars Apr 11 '18 at 15:33
cluster = filter(lambda x:x[1], cluster) – Kenstars Apr 11 '18 at 15:35
@Antry , I think the form of slicing however is not available in python2.x , could you confirm – Kenstars Apr 11 '18 at 15:36

score 0 · Answer 2 · answered Apr 11 '18 at 16:04

0

You can try any of these method :

data=[[0, "we break dance not hearts by Short Stack is my ringtone.... i LOVE that !!!.....\n"],
[1, "I want to write a . I think I will.\n"],
[2, "@va_stress broke my twitter..\n"],
[3, "\" &quot;Y must people insist on talking about stupid politics on the comments of a bubblegum pop . Sorry\n"],
[4, "aww great  &quot;Picture to burn&quot;\n"]]


print(list(map(lambda x:x[1].strip(),data)))

or

print([i[1].strip() for i in data])

output:

['we break dance not hearts by Short Stack is my ringtone.... i LOVE that !!!.....', 'I want to write a . I think I will.', '@va_stress broke my twitter..', '" &quot;Y must people insist on talking about stupid politics on the comments of a bubblegum pop . Sorry', 'aww great  &quot;Picture to burn&quot;']

answered Apr 11 '18 at 16:04

Aaditya Ura

12,007
7
50
88

I'm sorry but It prints 1, 2 ,3 ,4 ,5 too many times. like ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '1', '1', '1', '1', '1', '1', '1', '1', '1', '1', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '3', '3', '3', '3', '3', '3', '3', '3', '3', '3', '4', '4', '4', '4', '4', '4', '4', '4', '4', '4', '5', '5', '5', '5', '5', '5', '5', '5', '5', '5', '6', '6', '6', '6', '6', '6', '6', '6', '6' – Viral Patel Apr 11 '18 at 16:39
Mean It is just getting the first character of each line so if It is a line number [21,'xxx'] it prints '2' ,if It is a line number [331,'xxx'] it prints '3' – Viral Patel Apr 11 '18 at 16:49

Artemis · Answer 3 · 2018-04-11T16:14:39.690

Try this:

data=eval('['+(open('file.txt').read().replace('\n', ', ')[:-2])+']')
result=[]
for i in data:
    data.append(i[1])

The last 3 lines are pretty obvious, but here's what the first one does:

open('file.txt').read() opens the file and gets the contents
.replace('\n', ', ')[:-2] replaces the newlines with ,, except the last, so that it's formatted like a list. Skip [:-2]it if the last line doesn't end in a newline.
'['+...+']' adds [ and ] for more formatting as a list.
data=eval(...) makes creates the list and assigns it to data.

Just in case here is what the final lines do:

empty list created and assigned to result
i assigned to each value in data for the following line:
appends the second value of each list within data to result.

How can I get the nth element of String for list of list in python?

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