# Code Disciples

A blog for all things code

Sun 01 May 2022

# Swapping Variables in Python - How & Why

Posted by Abhishek Pednekar in Python

In today's article, we will see how to swap the values of two variables in Python. More importantly, we will understand why this works.

Traditionally, variable swapping in any language involves the introduction of a temporary variable to hold a value.

```x = 1
y = 2

temp = x
x = y
y = temp

# Will output x = 2
print(f"x = {x}")

# Will output y = 1
print(f"y = {y}")
```

Python can do this in one line.

```x, y = y, x
```

The output will be as expected.

```# Will output x = 2
print(f"x = {x}")

# Will output y = 1
print(f"y = {y}")
```

## Why does this work?

To understand why this works, we need to delve into the world of tuples. Tuples are immutable data structures in Python. Traditionally, a tuple is represented as x = (1, 2). Its elements can be accessed using the index values.

```x = (1, 2)

# Will output 1
print(x[0])

# Will result in an error
# 'tuple' object does not support item assignment

x[0] = 2
```

While we usually represent tuples using `()` brackets, a tuple can also be written as `x = 1, 2`.

```x = 1, 2

# Will output <class 'tuple'>
print(type(x))
```

In addition to using the index values, we can extract values from tuples by using the unpacking syntax.

```x, y = 1, 2

# Will output x = 1, y = 2
print(f"x = {x}, y = {y}")

x, y, *z = 1, 2, 3, 4

# Will output x = 1, y = 2, z = [3, 4]
print(f"x = {x}, y = {y}, z = {z}")
```

We can, therefore, use the unpacking method to swap variables as well.

```x, y = 1, 2

# Will output y, x = 2, 1
print(f"y, x = {y}, {x}")

# Variables are swapped!
x, y = y, x
```