# Bisect_left Function Of Bisect Module In Python

bisect_left

## Function Signature:

bisect_left(pythonList, newElement, lo=0, hi=len(a));

## Parameters:

pythonList – The Python list whose elements are in sorted order.

newElement –  The new element for which the position is to be found in the already sorted Python list.

lo – The lowest position of the search interval to be used as a heuristic.

hi – The highest position of the search interval to used as  a heuristic.

## Return Value:

The position at which the element can be inserted into the Python list while maintaining the sorted order of the list.

## Method Overview:

• The bisect_left() function finds and returns the position at which an element can be inserted into a Python list while maintaining the sorted order of the Python list. If the list already has elements with the same value as the new element, the insertion point is to the left of first such element.
• The position returned by the bisect_left() can be used as the parameter to the list.insert() to get the new element inserted into the list.

## Example:

 # Example Python program that finds the insertion # point of an element on an already sorted list import heapq import bisect   # class definition for a Currency Note class CurrencyNote:         def __init__(self, value):         self.value = value             def __eq__(self, anotherNote):         return self.value == anotherNote.value       def __lt__(self, anotherNote):         return self.value < anotherNote.value             def __repr__(self):         return "A %d dollar note"%self.value          # Currency note objects of various sovereign values c1 = CurrencyNote(1) c2 = CurrencyNote(10) c3 = CurrencyNote(20) c4 = CurrencyNote(50) c5 = CurrencyNote(100)   # A Python list as wallet wallet = [c2, c3, c1, c4, c5]   # Show wallet contents print(wallet)   # Create a min heap heapq.heapify(wallet)   # Sort the wallet sortedWallet = heapq.nsmallest(len(wallet), wallet)   # Show the sorted wallet for note in sortedWallet:     print(id(note))   # Find the insertion point ( to the left of an existing element, if the element exists) newNote = CurrencyNote(20) print("Id of the new note is: %s"%id(newNote)) insertionPoint = bisect.bisect_left(sortedWallet, newNote) print("Position of the newly inserted note in the wallet:") print(insertionPoint)   # Insert the element sortedWallet.insert(insertionPoint, newNote)   # Show the sorted wallet with the new note inserted for note in sortedWallet:     print(id(note))

## Output:

 [A 10 dollar note, A 20 dollar note, A 1 dollar note, A 50 dollar note, A 100 dollar note] 4320544848 4320544176 4321526112 4321526304 4321526448 Id of the new note is: 4321527696 Position of the newly inserted note in the wallet: 2 4320544848 4320544176 4321527696 4321526112 4321526304 4321526448