This short article shows how to use the module `bisect`

from the Python standard library.

Are you familiar with the module `bisect`

from the Python π standard library?

It is a small module to help you work with sorted lists.
If you have a sorted list and a new value, you can find the index where the new value would go by using the method `bisect`

:

```
>>> value = 22
>>> ordered_values = [1, 5, 19, 23]
# `value` would go at index 3 -^
>>> import bisect
>>> bisect.bisect(ordered_values, value)
3 # the index where `value` would go
>>> ordered_values.insert(3, value)
>>> ordered_values
[1, 5, 19, 22, 23]
```

The function `bisect`

tells you where a value *would* go...
But if you want to insert it, `bisect`

can also do that for you!
Just use the method `insort`

:

```
>>> ordered_values
[1, 5, 19, 22, 23]
# Let's add 21 in there, preserving the order:
>>> bisect.insort(ordered_values, 21)
>>> ordered_values
[1, 5, 19, 21, 22, 23]
```

The module `bisect`

has four more methods: `bisect_left`

, `bisect_right`

, `insort_left`

, and `insort_right`

...
The `_left`

and `_right`

tell you where to place ties (elements that are equal).

The methods `bisect`

and `insort`

, shown above, match their `_right`

variants.

This article was generated automatically from this thread I published on Twitter @mathsppblog. Then it was edited lightly.

I hope you learned something new! If you did, consider following the footsteps of the readers who bought me a slice of pizza π. Your contribution boosts my confidence and helps me produce this content for you.

- Python 3 docs, The Python Standard Library,
`bisect`

, https://docs.python.org/3/library/bisect.html [last accessed 10-08-2022];