**by BehindJava**

# What are List Comprehensions in Python with Syntax and Examples

In this tutorial we are going to learn about List Comprehensions in Python with Syntax and Examples.

In addition to sequence operations and list methods, Python includes a more advanced operation called a list comprehension.

List comprehensions allow us to build out lists using a different notation. You can think of it as essentially a one line for loop built inside of brackets.

For a simple example:

**Example 1:**

```
# Grab every letter in string
lst = [x for x in 'word']
# Check
lst
Output-
['w', 'o', 'r', 'd']
```

This is the basic idea of a list comprehension. If you’re familiar with mathematical notation this format should feel familiar for example: x^2 : x in { 0,1,2…10 }

Let’s see a few more examples of list comprehensions in Python:

**Example 2:**

```
# Square numbers in range and turn into list
lst = [x**2 for x in range(0,11)]
lst
Output-
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
```

**Example 3**

Let’s see how to add in if statements:

```
# Check for even numbers in a range
lst = [x for x in range(11) if x % 2 == 0]
lst
Output-
[0, 2, 4, 6, 8, 10]
```

**Example 4**

Can also do more complicated arithmetic:

```
# Convert Celsius to Fahrenheit
celsius = [0,10,20.1,34.5]
fahrenheit = [((9/5)*temp + 32) for temp in celsius ]
Fahrenheit
Output-
[32.0, 50.0, 68.18, 94.1]
```

**Example 5**

We can also perform nested list comprehensions, for example:

```
lst = [ x**2 for x in [x**2 for x in range(11)]]
lst
output-
[0, 1, 16, 81, 256, 625, 1296, 2401, 4096, 6561, 10000]
```

After this lecture you should feel comfortable reading and writing basic list comprehensions.