Join strings from for loop into a single line

Question

I have a grammar tag producing nltk block which is,

    sent_text = nltk.sent_tokenize(text) # this gives us a list of sentences
    # now loop over each sentence and tokenize it separately
    for sentence in sent_text:
          tokenized_text = nltk.word_tokenize(sentence)
          tagged = nltk.pos_tag(tokenized_text) 
          for word, tag in tagged:
               print(tag)

This gives me the following output,

    DT
    JJ
    NN
    NN
    VBD
    IN
    DT
    JJ
    NN

However, I want the output to single lined like

    DT JJ NN NN VBD IN DT JJ NN

How do I do this?

The python3 `print` function has an `end` parameter, set it to `' '`, e.g. `print(tag, end=' ')`: see https://docs.python.org/3.5/library/functions.html?highlight=print%20function#print — AChampion, Jun 05 '16 at 03:11
@AChampion there is no use copying my answer in the comments — Tilak Maddy, Jun 05 '16 at 07:40

score 2 · Answer 1 · answered Jun 05 '16 at 03:11

If you want not just print, but store the result in a string, you can use str.join() and a single list comprehension:

tags = [tag 
        for sentence in sent_text 
        for _, tag in nltk.pos_tag(nltk.word_tokenize(sentence))]
result = " ".join(tags)
print(result)

Note that the _ is a common variable name for throwaway variables.

score 1 · Answer 2 · edited Jun 05 '16 at 03:35

1

Do this

print (tag, end=" ")

That should leave a space and not go to next line.

edited Jun 05 '16 at 03:35

heemayl

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answered Jun 05 '16 at 03:13

Tilak Maddy

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I am using python 2.7 so does not work. Gives syntax errors – Nikhil Raghavendra Jun 05 '16 at 03:18

Marlon Abeykoon · Answer 3 · 2016-06-05T03:19:59.663

1

I dont think ultimately you want to print the whole string and keep using print(tag, end = ' ') so assign it to new variable is explained below. Initialize a variable tag_str on top and use it after print statement like this.

tag_str += ' '

tag_str += tag

edited Jun 05 '16 at 03:19

answered Jun 05 '16 at 03:14

Marlon Abeykoon

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score 1 · Answer 4 · answered Jun 05 '16 at 03:29

1

If you aren't using Python 3, you could write directly to sys.stdout, which would enable you to skip the newline character.

answered Jun 05 '16 at 03:29

mcchucklezz

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score 1 · Answer 5 · answered Jun 05 '16 at 03:44

1

If you are using python 2.x use print(tag,), the , puts output in the same line. so you can use print (tag + ' ',)

If you are using python 3 use print(tag, end="") or print(tag, end=" ") depending on whether you want whitespace or not.

answered Jun 05 '16 at 03:44

Aravind Voggu

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Join strings from for loop into a single line

5 Answers5