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SyntaxError: expected ':'

What it means

Lines that start a block, such as if, elif, else, for, while, def and class lines, must end with a colon. Python reached the end of one of these lines without finding it.

1. Forgetting the colon after an `if`

This raises the error

Broken
temperature = 31
if temperature > 30
print("It is a hot day")
Output
Traceback (most recent call last):
  File "<exec>", line 2
    if temperature > 30
                       ^
SyntaxError: expected ':'

The fix

Fixed
temperature = 31
if temperature > 30:
print("It is a hot day")
Output
It is a hot day

The colon marks the end of the condition and the start of the indented block below it.

Try fixing it yourself in the editor

2. Forgetting the colon after `def` or `for`

This raises the error

Broken
def greet(name)
print("Hello,", name)
greet("Ada")
Output
Traceback (most recent call last):
  File "<exec>", line 1
    def greet(name)
                   ^
SyntaxError: expected ':'

The fix

Fixed
def greet(name):
print("Hello,", name)
greet("Ada")
Output
Hello, Ada

A function definition needs the colon after its closing bracket, just like for, while and class lines do.

Try fixing it yourself in the editor

3. Writing `else if` instead of `elif`

This raises the error

Broken
x = 3
if x > 5:
print("big")
else if x > 2:
print("medium")
Output
Traceback (most recent call last):
  File "<exec>", line 4
    else if x > 2:
         ^^
SyntaxError: expected ':'

The fix

Fixed
x = 3
if x > 5:
print("big")
elif x > 2:
print("medium")
Output
medium

Python spells it elif. After else, Python expects the colon straight away, so the if that follows looks like a missing colon.

Try fixing it yourself in the editor

When you see this error, check

  • Check the end of every if, elif, else, for, while, def, class, try, except and with line for a colon.
  • Write elif, not else if.
  • Use a colon :, not a semicolon ;.
  • Put the colon after the closing bracket: def greet(name):, not def greet(name:).

Related errors

All Python errors · How to read a traceback · Step through your code