This module provides support for maintaining a list in sorted order
without having to sort the list after each insertion. For long lists
of items with expensive comparison operations, this can be an
improvement over the more common approach. The module is called
`bisect` because it uses a basic bisection algorithm to do its work.
The source code may be most useful as a working example of the
algorithm (the boundary conditions are already right!).

The following functions are provided:

bisect.bisect_left(list, item[, lo[, hi]])

Locate the proper insertion point for

iteminlistto maintain sorted order. The parametersloandhimay be used to specify a subset of the list which should be considered; by default the entire list is used. Ifitemis already present inlist, the insertion point will be before (to the left of) any existing entries. The return value is suitable for use as the first parameter tolist.insert(). This assumes thatlistis already sorted.New in version 2.1.

bisect.bisect_right(list, item[, lo[, hi]])

Similar to

bisect_left(), but returns an insertion point which comes after (to the right of) any existing entries ofiteminlist.New in version 2.1.

bisect.bisect(...)

Alias forbisect_right().

bisect.insort_left(list, item[, lo[, hi]])

Insert

iteminlistin sorted order. This is equivalent tolist.insert(bisect.bisect_left(list, item, lo, hi), item). This assumes thatlistis already sorted.New in version 2.1.

bisect.insort_right(list, item[, lo[, hi]])

Similar to

insort_left(), but insertingiteminlistafter any existing entries ofitem.New in version 2.1.

bisect.insort(...)

Alias forinsort_right().

The `bisect()` function is generally useful for categorizing numeric
data. This example uses `bisect()` to look up a letter grade for an
exam total (say) based on a set of ordered numeric breakpoints: 85 and
up is an ‘A’, 75..84 is a ‘B’, etc.

```
>>> grades = "FEDCBA"
>>> breakpoints = [30, 44, 66, 75, 85]
>>> from bisect import bisect
>>> def grade(total):
... return grades[bisect(breakpoints, total)]
...
>>> grade(66)
'C'
>>> map(grade, [33, 99, 77, 44, 12, 88])
['E', 'A', 'B', 'D', 'F', 'A']
```

Unlike the `sorted()` function, it does not make sense for the
`bisect()` functions to have *key* or *reversed* arguments because
that would lead to an inefficent design (successive calls to bisect
functions would not “remember” all of the previous key lookups).

Instead, it is better to search a list of precomputed keys to find the index of the record in question:

```
>>> data = [('red', 5), ('blue', 1), ('yellow', 8), ('black', 0)]
>>> data.sort(key=lambda r: r[1])
>>> keys = [r[1] for r in data] # precomputed list of keys
>>> data[bisect_left(keys, 0)]
('black', 0)
>>> data[bisect_left(keys, 1)]
('blue', 1)
>>> data[bisect_left(keys, 5)]
('red', 5)
>>> data[bisect_left(keys, 8)]
('yellow', 8)
```