Python 2.7.3 IndentationError: expected an indented block - cant find mistake

Question

I am new to python and trying to submit my HW on Coursera Data Science course. The environment there is VM running Python 2.7.3, the file tweet_sentiment.py I am trying to run has the following script within it:

import sys
import json

def hw():
    print 'Hello, world!'

def lines(fp):
    print str(len(fp.readlines()))

def main():
    sent_file = open(sys.argv[1])
    tweet_file = open(sys.argv[2])
    # hw()
    # lines(sent_file)
    # lines(tweet_file)

    myfile = open(sys.argv[1], 'r')
    lines = myfile.readlines()
    mydict = {}
    for line in lines:
    key, value = line.split("\t")
        mydict[key] = int(value)

    twit_file = open(sys.argv[2], 'r')
    twit_lines = twit_file.readlines()

    mylist = []
    for line in twit_lines:
    mylist.append(json.loads(line))

    for listik in mylist:
    twit_value = 0
    twit_text = listik["text"]
    twit_words = twit_text.split()
    for word in twit_words:
        if word in mydict:
        twit_value =  twit_value + 1
    print float(twit_value)


if __name__ == '__main__':
    main()

When running $ python tweet_sentiment.py I am getting the following error:

    File "tweet_sentiment.py", line 25
    key, value = line.split("\t")
      ^
IndentationError: expected an indented block

Thanks for any hints! Sergey

Solution 1

Be careful! You're mixing tabs and spaces for indenting.

Often a tab is displayed as the equivalent of 8 spaces. So, when using the common practice of 4 spaces it looks like 2 levels of indentation, but is really only one.

When I examine your code in the editor, I can see that you've got in at least two places. Replace those tabs with 4 spaces.

Solution 2

As it says, you have an indentation error. Line 25 should be corrected to this:

def main():

...

    for line in lines:
        key, value = line.split("\t")
        mydict[key] = int(value)

Solution 3

You have to indent the line after a for block. Your code should look like:

for line in lines:
    key, value = line.split("\t")
    mydict[key] = int(value)

Solution 4

Your code must be like this:

for line in lines:
    key, value = line.split("\t")
    mydict[key] = int(value)

It's the same for all other for's.

View more solutions

Comments

[Levon]

+1 Just to add to what @gnibbler says, PEP8 warns about just this, and recommends the use of spaces over tabs. (4 spaces per indentation level)

[Sergey Samusev]

Thanks! Sorry for posting this mess,I looked like I am asking really basic question. Indentation was actually well organized in my file, but when copying it to post, formatting got lost and I did not check that. Eventually my file was successfully executed by the course script which checks assignment and results went out right. I am not sure why it did not work when running on VM. Thanks for prompt response!

[Sergey Samusev]

Thanks! Sorry for posting this mess,I looked like I am asking really basic question. Indentation was actually well organized in my file, but when copying it to post, formatting got lost and I did not check that. Eventually my file was successfully executed by the course script which checks assignment and results went out right. I am not sure why it did not work when running on VM. Thanks for prompt response!

[kirbyfan64sos]

@SergeySamusev: You're welcome! The error was an indentation error. Might have had something to do with...well...I don't really know. All I can say is...good luck! Maybe the indentation was like one space off or didn't correlate with the rest of the file. I make that seemingly novice mistake all the time.