What is numpy.left_shift() in Python?

Overview

The numpy.left_shift() method is used to shift bits to the left x2 times by appending 0s at the right of x1.

Note: The left shift operation is equivalent to the multiplying x1 by 222^2.

Syntax

numpy.left_shift(arr1,

                 arr2,

                 /,

                 out=None,

                 *,

                 where=True,

                 casting='same_kind',

                 order='K',

                 dtype=None,

                 ufunc 'left_shift')

Parameters

It takes the following argument values.

  • arr1: Integer number or array_like instance.
  • arr2: Integer number or array_like instance. It shows the number of 0s which will be appended to x1. If x1.shape is not equal to x2.shape, then its dimensions should be able to be broadcasted.
  • out: A location where results are stored. It can be ndarray, None, and a tuple of ndarray. Its default value is None.
  • where: Array-like instance. It shows a condition where broadcasting is applied. Its default value is True.
  • **kwargs: The other arguments are optional and show keyword argument values.

Return value

It returns either a scalar value or an integer array.

  • out: It returns x1 with x2 times a left-shifted number.

Case 1: Where x1 & x2 are both scalar values

# Case#1 where x1 & x2 both are scalar values.
# loading numpy library
import numpy as np
# defining x1 and x2 numbers
x1= 10
x2= 2
# invoking left_shift() method to perform left shift operation
out= np.left_shift(x1, x2)
# print output on console.
print("After left shifting 2 bit : ", out)
  • Line 5–6: We define x1 and x2 as integer values.
  • Line 8: We call left_shift() with x1 as 10 and x2 as 2 to left shift x1 by 2 times. It prints 40 because the left shift is also equivalent to 10∗2210*2^2.
  • Line 10: We print the left-shifted number to the console.

Case 2: Where x1 is a scalar while x2 is an integer array

# Case#2 where x1 is scalar while x2 is integer array
# loading numpy library
import numpy as np
# defining an integer as well as integer array
x1= 5
x2= [1, 2, 3]
# print numbers on console
print("Input number : ", x1)
print("Number of bit shift : ", x2)
# left x1, x2 times
out= np.left_shift(x1, x2)
# print numbers on console
print("Output array after left shifting: ", out)
  • Line 5–6: We define x1 as5 (scalar) while we define x2 as [1, 2, 3] (integer array).
  • Line 8–9: We print x1 as well as x2 to the console.
  • Line 11: The np.left_shift(x1, x2) statement shifts x1 values, x2 times at each index of arrays.
  • Line 13: We print the left-shifted number to the console.

Case 3: Where x1 & x2 are both integer arrays

# Case#3 where x1 & x2 both are integer arrays.
# loading numpy library
import numpy as np
# defining two integer arrays
x1= [2, 8, 15]
x2= [3, 4, 5]
# shows above arrays on console
print("Input array : ", x1)
print("Number of bit shift : ", x2)
# invoking left_shift() to shift x1, x2 times
out= np.left_shift(x1, x2)
# results on the console
print("Output array after left shifting: ", out)
  • Line 5–6: We define x1 as well as x2 as two integer arrays.
  • Line 8–9: We print the x1 and x2 arrays to the console.
  • Line 11: The np.left_shift(x1, x2) statement will left shift x1 array values x2 times each time the number parallel to each index.
  • Line 13: We print the left-shifted results as integer array to the console: [ 16 128 480].

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