numpy.left_shift() in Python

numpy.left_shift() function is used to Shift the bits of an integer to the left.

The bits are shifted to the left by appending arr2 0s(zeroes) at the right of arr1. Since the internal representation of numbers is in binary format, this operation is equivalent to multiplying arr1 by 2**arr2. For example, if the number is 5 and we want to 2 bit left shift then after left shift 2 bit the result will be 5*(2^2) = 20

Syntax : numpy.left_shift(arr1, arr2, /, out=None, *, where=True, casting=’same_kind’, order=’K’, dtype=None, ufunc ‘left_shift’)

Parameters :
arr1 : array_like of integer type
arr2 : array_like of integer type
Number of zeros to append to arr1.The value of arr2 should be positive integer.

out : [ndarray, optional] A location into which the result is stored.
  -> If provided, it must have a shape that the inputs broadcast to.
  -> If not provided or None, a freshly-allocated array is returned.

**kwargs : allows you to pass keyword variable length of argument to a function. It is used when we want to handle named argument in a function.

where : [array_like, optional]True value means to calculate the universal functions(ufunc) at that position, False value means to leave the value in the output alone.

Return : array of integer type.
Return arr1 with bits shifted arr2 times to the left. This is a scalar if both arr1 and arr2 are scalars.

Code #1 : Working

# Python program explaining
# left_shift() function

import numpy as geek
in_num = 5
bit_shift = 2

print ("Input  number : ", in_num)
print ("Number of bit shift : ", bit_shift )

out_num = geek.left_shift(in_num, bit_shift)
print ("After left shifting 2 bit  : ", out_num)

Output :

Input  number :  5
Number of bit shift :  2
After left shifting 2 bit  :  20

Code #2 :

# Python program explaining
# left_shift() function

import numpy as geek

in_arr = [2, 8, 15]
bit_shift =[3, 4, 5]

print ("Input array : ", in_arr)
print ("Number of bit shift : ", bit_shift)

out_arr = geek.left_shift(in_arr, bit_shift)
print ("Output array after left shifting: ", out_arr)

Output :

Input array :  [2, 8, 15]
Number of bit shift :  [3, 4, 5]
Output array after left shifting:  [ 16 128 480]