# sort¶

## Description¶

Sorts the list in place.

## Syntax¶

list. sort([cmp[, key[, reverse]]])

cmp
Optional. Specifies a custom comparison function of two arguments (list items) which should return a negative, zero or positive number depending on whether the first argument is considered smaller than, equal to, or larger than the second argument: The default value is None.
key
Optional. Specifies a function of one argument that is used to extract a comparison key from each list element. The default value is None.
reverse
Optional. A boolean value. If set to True, then the list elements are sorted as if each comparison were reversed.

None

O(n log n)

## Remarks¶

In general, the key and reverse conversion processes are much faster than specifying an equivalent cmp function. This is because cmp is called multiple times for each list element while key and reverse touch each element only once.

## Example 1¶

```>>> l = [1, 3, 2]
>>> l.sort()
>>> l
[1, 2, 3]
```

## Example 2¶

```>>> # this example shows how to use cmp argument
>>> l = ['a', 'B', 'A', 'c']
>>> l.sort()
>>> l
['A', 'B', 'a', 'c']
>>> l = ['a', 'B', 'A', 'c']
>>> l.sort(lambda x, y: cmp(x.lower(), y.lower()))
>>> l
['a', 'A', 'B', 'c']
```

## Example 3¶

```>>> l = ['a', 'B', 'c']
>>> l.sort()
>>> l
['B', 'a', 'c']
>>> l.sort(key=lambda x: x.lower())
>>> l
['a', 'B', 'c']
```

## Example 4¶

```>>> l = [1, 3, 2]
>>> l.sort()
>>> l
[1, 2, 3]
>>> l.sort(reverse=True)
>>> l
[3, 2, 1]
```