---
title: How are arguments passed by value or by reference in python?
description: How are arguments passed by value or by reference in python?
---
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# How are arguments passed by value or by reference in python?
Pass by value: Copy of the actual object is passed. Changing the value of the copy of the object will not change the value of the original object.
Pass by reference: Reference to the actual object is passed. Changing the value of the new object will change the value of the original object.
In Python, arguments are passed by reference, i.e., reference to the actual object is passed.
def appendNumber(arr):
arr.append(4)
arr = \[1, 2, 3\]
print(arr) #Output: =\> \[1, 2, 3\]
appendNumber(arr)
print(arr) #Output: =\> \[1, 2, 3, 4\]
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