Python中的 numpy.index()

numpy.core.defchararray.index(arr, substring, start=0, end=None) ：在指定范围内查找子字符串的最低索引但是如果未找到子字符串，则会引发 ValueError。

Parameters:
arr : array-like or string to be searched.
substring : substring to search for.
start, end : [int, optional] Range to search in.

Returns : An integer array with the lowest index of found sub-string, raises ValueError if substring is not found.

代码#1：

# Python Program illustrating 
# numpy.char.index() method 
import numpy as np 
  
arr = ['this is geeks for geek']
  
print ("arr : ", arr)
  
print ("\nindex of 'geeks' : ", np.char.index(arr, 'geeks'))

输出：

arr :  ['this is geeks for geek']

index of 'geeks' : [8]

代码#2：

# Python Program illustrating 
# numpy.char.index() method 
import numpy as np 
  
arr = ['this is geeks for geek']
  
print ("\nindex of 'geeks' : ", np.char.index(arr, 'geeks', start = 2))
print ("\nindex of 'geeks' : ", np.char.index(arr, 'geeks', start = 10))
print ("\nindex of 'geek' : ", np.char.index(arr, 'geek', start = 10))

输出：

index of 'geeks' : [8]
ValueError: substring not found
index of 'geek' : [18]