Python IndentationError unindent does not match any outer indentation level [duplicate]

Question

I'm a beginner in python,

I have this error :

Error : 
def on_data(self,data):
                      ^
IdentationError : unindent does not match any outer indentation level

I code with notepad++ in windows 8.1. I don't understand why I have this error, I have paid attention about tabs and space.

I want to save data in self.file

Here is my code :

from tweepy import OAuthHandler
from tweepy.streaming import StreamListener
from tweepy import Stream
import tweepy
import time



class StdOutListener(StreamListener):

    def __init__(self,file):
        self.file = file

    def on_data(self, data):

        print data
        self.file.write(data)
        return True

    def on_error(self, status):
        print status


def main() :
    file = open('work.txt','w')
    listn = StdOutListener(file)
    consumer_key=""
    consumer_secret=""

    access_token=""
    access_token_secret=""

    auth = tweepy.OAuthHandler(consumer_key, consumer_secret)
    auth.set_access_token(access_token, access_token_secret)
    #api = tweepy.API(auth)

    #filename=open('helloworld.txt','r')
    #f=filename.readlines()
    #filename.close()

    #for line in f:
    #   api.update_status(line)

    stream = Stream(auth, listn)
    stream.filter(track=['lol'])
    file.close()

Answer 1

You are mixing tabs and spaces. Don't do that. Specifically, the __init__ function body is indented with tabs while your on_data method is not.

Here is a screenshot of your code in my text editor; I set the tab stop to 8 spaces (which is what Python uses) and selected the text, which causes the editor to display tabs with continuous horizontal lines:

You have your editor set to expanding tabs to every fourth column instead, so the methods appear to line up.

Run your code with:

python -tt scriptname.py

and fix all errors that finds. Then configure your editor to use spaces only for indentation; a good editor will insert 4 spaces every time you use the TAB key.

Answer 2

You have mixed indentation formatting (spaces and tabs)

On Notepad++

Change Tab Settings to 4 spaces

Go to Settings -> Preferences -> Tab Settings -> Replace by spaces

Fix the current file mixed indentations

Select everything CTRL+A

Click TAB once, to add an indentation everywhere

Run SHIFT + TAB to remove the extra indentation, it will replace all TAB characters to 4 spaces.