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?

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)

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.

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 :-)

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.

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

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

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.

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

Or – you have mixed space and tab characters

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")

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.

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

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

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

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.

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

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")

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.

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!")

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

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.

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

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.

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

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

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.

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

For SPYDER users: I’m using spyder 3.3.2 with python 3.7.1 and I solved this, setting indentation to use tabs, with the following steps, click on:

• Tools.
• Preferences.
• Editor.
• Advanced settings.
• Indentation characters -> Tabs.

Then I reset the “unidented” line using tab key.

For some reason, without this setting, I got the ghost IndentationError sometimes.

For example:

1. def convert_distance(miles):
2.   km = miles * 1.6
3.   return km

In this code same situation occurred for me. Just delete the previous indent spaces of line 2 and 3, and then either use tab or space. Never use both. Give proper indentation while writing code in python. For Spyder goto Source > Fix Indentation. Same goes to VC Code and sublime text or any other editor. Fix the indentation.

This happens mainly because of editor .Try changing tabs to spaces(4).the best python friendly IDE or Editors are pycharm ,sublime ,vim for linux.
even i too had encountered the same issue , later i found that there is a encoding issue .i suggest u too change ur editor.