operations with empty strings | index () function



numpy.core.defchararray.index (arr, sub, start = 0, end = None) — this is another function for doing string operations in numpy. It returns the lowest index in the string where the sub string is found for each element in arr . Returns the error value if sub is not contained in the range [start, end] .

Parameters:
arr : array_like of str or unicode.
sub: [str or unicode] The substring which to be searched.
start: [ int, optional] The starting location in each string.
end: [int, optional] The ending location in each string.

Returns: [ndarray] Output array of int.

Code # 1:

# Python program explaining
# numpy.char.index () method

 
# numpy import

import numpy as geek

  
# input arrays

in_arr = geek.array ([ `aAaAaA` , `baA` , ` abBABba` ])

print ( " Input array: " , in_arr) 

  
# output arrays

out_arr = geek.char.index (in_arr, sub = `a` )

print ( "Output array:" , out_arr)  < / p>

Output:

 Input array: [`aAaAaA`` baA` `abBABba`] Output array: [0 1 0] 

Code # 2:

# Python program explaining
# numpy.char.index () method

 
# numpy import

import numpy as geek

 
# input arrays

in_arr = geek.array ([ `aAaAaA` , ` aA` , `abBABba` ])

print ( "Input array:" , in_arr ) 

 
# output arrays

out_arr = geek.char.index (in_arr, sub = `A` , start = 1 , end = 4 )

print ( "Output array:" , out_arr) 

Output :

 Input array: [`aAaAaA`` aA` `abBABba`] Output array: [1 1 3]  

Code # 3: if the substring is not found, call ValueErro r.

# Python program explaining
# numpy.char.index () method

 
# numpy import

import numpy as geek

 
# input arrays

in_arr = geek.array ([ `aAaAaA` , ` aA` , `abBABba` ])

print ( "Input array:" , in_arr) 

  
# output arrays

out_arr = geek.char.index (in_arr, sub = ` A` , start = 3 , end = 7 )

print ( "Output array:" , out_arr) 

Output:

 ValueError: substring not found