Tuple with One Item in Python

In Python, tuple with a single item has a specific syntax requirement to avoid confusion with parentheses used for grouping expressions.

Using a Trailing Comma

The most common way to create a single-item tuple is by placing a trailing comma. This tells Python that given expression is a tuple.

# Correct way to define a single-item tuple
t = (5,)
print(t)         
print(type(t))   

(5,)
<class 'tuple'>

Common Mistake: Missing the Trailing Comma

If we miss the trailing comma, Python treats the parentheses as grouping for an expression instead of defining a tuple.

# Incorrect - This is an integer, not a tuple
t = (5)
print(t)          
print(type(t))   

5
<class 'int'>

Using the tuple() Constructor

Using tuple constructor works only for iterable items (like string, list etc).

# Using tuple() with a single-item list
t = tuple([5])
print(t)           
print(type(t)) 

# using a string iterable inside tuple() constructor
t = tuple("A")
print(t)   
print(type(t)) 

# Below code would not work as integer is not iterable
# t = tuple(5)