680
votes

When I compile the Python code below, I get

IndentationError: unindent does not match any outer indentation level


import sys

def Factorial(n): # Return factorial
    result = 1
    for i in range (1,n):
        result = result * i
    print "factorial is ",result
    return result

Why?

30
and probably range(1, n+1) will be better, if you want to include 'n' in your computation :-)Abgan
I had the same error, but I happened to indent a method way up in the code slightly to the left, which gave this error at the bottom of the next method after it. So this error can occur not only from mixing tabs and spaces.Prof. Falken
I am using Sublime Text 3. I have a Django project. I fixed the error using View > Indentation > Intent Using Spacesabhimanyuaryan
Had this issue in pycharm, adjusting tabs and spacing in configs didn't work. The issue was I had an ~/.editorconfig file that was overriding the pycharm configuration.Ken Myers
I found using IDLE makes it much easier to find indentation issues. It will clearly find indentation errors that most editors wont find.Dennis Gathagu

30 Answers

784
votes

Other posters are probably correct...there might be spaces mixed in with your tabs. Try doing a search & replace to replace all tabs with a few spaces.

Try this:

import sys

def Factorial(n): # return factorial
    result = 1
    for i in range (1,n):
        result = result * i
    print "factorial is ",result
    return result

print Factorial(10)
302
votes

IMPORTANT: Spaces are the preferred method - see PEP008 Indentation and Tabs or Spaces?. (Thanks to @Siha for this.)

For Sublime Text users:

Set Sublime Text to use tabs for indentation: View --> Indentation --> Convert Indentation to Tabs

Uncheck the Indent Using Spaces option as well in the same sub-menu above. This will immediately resolve this issue.

147
votes

To easily check for problems with tabs/spaces you can actually do this:

python -m tabnanny yourfile.py

or you can just set up your editor correctly of course :-)

44
votes

Are you sure you are not mixing tabs and spaces in your indentation white space? (That will cause that error.)

Note, it is recommended that you don't use tabs in Python code. See the style guide. You should configure Notepad++ to insert spaces for tabs.

25
votes

Whenever I've encountered this error, it's because I've somehow mixed up tabs and spaces in my editor.

15
votes

If you use Python's IDLE editor you can do as it suggests in one of similar error messages:

1) select all, e.g. Ctrl + A

2) Go to Format -> Untabify Region

3) Double check your indenting is still correct, save and rerun your program.

I'm using Python 2.5.4

14
votes

If you are using Vim, hit escape and then type

gg=G

This auto indents everything and will clear up any spaces you have thrown in.

10
votes

The line: result = result * i should be indented (it is the body of the for-loop).

Or - you have mixed space and tab characters

9
votes

On Atom

go to

Packages > Whitespace > Convert Spaces to Tabs

Then check again your file indentation:

python -m tabnanny yourFile.py

or

>python
>>> help("yourFile.py")
6
votes

If you use notepad++, do a "replace" with extended search mode to find \t and replace with four spaces.

6
votes

For Spyder users goto Source > Fix Indentation to fix the issue immediately

5
votes

Looks to be an indentation problem. You don't have to match curly brackets in Python but you do have to match indentation levels.

The best way to prevent space/tab problems is to display invisible characters within your text editor. This will give you a quick way to prevent and/or resolve indentation-related errors.

Also, injecting copy-pasted code is a common source for this type of problem.

4
votes

Just a addition. I had a similar problem with the both indentations in Notepad++.

  1. Unexcepted indentation
  2. Outer Indentation Level

    Go to ----> Search tab ----> tap on replace ----> hit the radio button Extended below ---> Now replace \t with four spaces

    Go to ----> Search tab ----> tap on replace ----> hit the radio button Extended below ---> Now replace \n with nothing

4
votes

I was using Jupyter notebook and tried almost all of the above solutions (adapting to my scenario) to no use. I then went line by line, deleted all spaces for each line and replaced with tab. That solved the issue.

4
votes

Using Visual studio code

If you are using vs code than, it will convert all mix Indentation to either space or tabs using this simple steps below.

  1. press Ctrl + Shift + p

  2. type indent using spaces

  3. Press Enter

3
votes

For what its worth, my docstring was indented too much and this also throws the same error

class junk: 
     """docstring is indented too much""" 
    def fun(): return   

IndentationError: unindent does not match any outer indentation level

2
votes

for Atom Users, Packages ->whitspace -> remove trailing whitespaces this worked for me

2
votes

I'm using Sublime text in Ubuntu OS. To fix this issue go to

view -> Indentation -> convert indentation to tabs

1
votes

It could be because the function above it is not indented the same way. i.e.

class a:
    def blah:
      print("Hello world")
    def blah1:
      print("Hello world")
1
votes

This is because there is a mix-up of both tabs and spaces. You can either remove all the spaces and replace them with tabs.

Or, Try writing this:

#!/usr/bin/python -tt

at the beginning of the code. This line resolves any differences between tabs and spaces.

1
votes

I had the same issue yesterday, it was indentation error, was using sublime text editor. took my hours trying to fix it and at the end I ended up copying the code into VI text editor and it just worked fine. ps python is too whitespace sensitive, make sure not to mix space and tab.

1
votes

Since I realize there's no answer specific to spyder,I'll add one: Basically, carefully look at your if statement and make sure all if, elif and else have the same spacing that is they're in the same line at the start like so:

def your_choice(answer):
    if answer>5:
        print("You're overaged")
    elif answer<=5 and answer>1: 
            print("Welcome to the toddler's club!")
    else:
            print("No worries mate!")
1
votes

I had a function defined, but it did not had any content apart from its function comments...

def foo(bar):
    # Some awesome temporary comment.
    # But there is actually nothing in the function!
    # D'Oh!

It yelled :

  File "foobar.py", line 69

                                ^
IndentationError: expected an indented block

(note that the line the ^ mark points to is empty)

--

Multiple solutions:

1: Just comment out the function

2: Add function comment

def foo(bar):
    '' Some awesome comment. This comment could be just one space.''

3: Add line that does nothing

def foo(bar):
    0

In any case, make sure to make it obvious why it is an empty function - for yourself, or for your peers that will use your code

1
votes

Firstly, just to remind you there is a logical error you better keep result=1 or else your output will be result=0 even after the loop runs.

Secondly you can write it like this:

import sys

def Factorial(n): # Return factorial
  result = 0
  for i in range (1,n):
     result = result * i

  print "factorial is ",result
  return result

Leaving a line will tell the python shell that the FOR statements have ended. If you have experience using the python shell then you can understand why we have to leave a line.

1
votes

I am using Sublime Text 3 with a Flask project. I fixed the error using View > Indentation > Tab Width: 4 after unselected Indent Using Spaces

1
votes

I got this error even though I didn't have any tabs in my code, and the reason was there was a superfluous closing parenthesis somewhere in my code. I should have figured this out earlier because it was messing up spaces before and after some equal signs... If you find anything off even after running Reformat code in your IDE (or manually running autopep8), make sure all your parentheses match, starting backwards from the weird spaces before/after the first equals sign.

0
votes

in my case, the problem was the configuration of pydev on Eclipse

pydev @ Eclipse

0
votes

If you use Komodo editor you can do as it suggests in one of similar error messages:

1) select all, e.g. Ctrl + A

2) Go to Code -> Untabify Region

3) Double check your indenting is still correct, save and rerun your program.

I'm using Python 3.4.2

0
votes

If you are using Sublime text for python development,you can avoid the error by using the package Anaconda.After installing Anaconda,

  1. open your file in sublime
  2. right click on the open spaces
  3. choose anaconda
  4. click on autoformat
  5. DONE Or Press CTRL+ALT+R.
0
votes

In intellij with python plugin, Ctrl + Shift + Alt to reformat the document fixed the indent/tab/spaces problem