numpy.diff() in Python (original) (raw)

Last Updated : 22 Jul, 2021

numpy.diff(arr[, n[, axis]]) function is used when we calculate the n-th order discrete difference along the given axis. The first order difference is given by out[i] = arr[i+1] – arr[i] along the given axis. If we have to calculate higher differences, we are using diff recursively.

Syntax: numpy.diff()
Parameters:
arr : [array_like] Input array.
n : [int, optional] The number of times values are differenced.
axis : [int, optional] The axis along which the difference is taken, default is the last axis.
Returns : [ndarray]The n-th discrete difference. The output is the same as a except along axis where the dimension is smaller by n.

Code #1 :

Python3

import numpy as geek

arr = geek.array([ 1 , 3 , 4 , 7 , 9 ])

print ( "Input array : " , arr)

print ( "First order difference : " , geek.diff(arr))

print ( "Second order difference : " , geek.diff(arr, n = 2 ))

print ( "Third order difference : " , geek.diff(arr, n = 3 ))

Output:

Input array : [1 3 4 7 9] First order difference : [2 1 3 2] Second order difference : [-1 2 -1] Third order difference : [ 3 -3]

Code #2 :

Python3

import numpy as geek

arr = geek.array([[ 1 , 2 , 3 , 5 ], [ 4 , 6 , 7 , 9 ]])

print ( "Input array : " , arr)

print ( "Difference when axis is 0 : " , geek.diff(arr, axis = 0 ))

print ( "Difference when axis is 1 : " , geek.diff(arr, axis = 1 ))

Output:

Input array : [[1 2 3 5] [4 6 7 9]] Difference with axis 0 : [[3 4 4 4]] Difference with axis 1 : [[1 1 2] [2 1 2]]

Similar Reads