numpy字符串操作 | lstrip()函数

numpy.core.defchararray.lstrip(arr, chars=None)是另一个在 numpy 中进行字符串操作的函数。它返回一个副本，其中删除了 arr 中每个元素的前导字符。

Parameters:
arr : array_like of str or unicode.
char : [str or unicode, optional] the set of characters to be removed. If omitted or None, it removes whitespace. The chars argument is not a prefix or suffix; it is all combinations of its values which we want to strip.

Returns : [ndarray] Output array of str or unicode, depending on input type.

代码#1：

# Python program explaining
# numpy.char.lstrip() method 
  
import numpy as geek
  
# input arrays  
in_arr = geek.array(['Sun', '  Moon  ', 'Star'])
print ("Input array : ", in_arr) 
  
out_arr = geek.char.lstrip(in_arr)
  
# whitespace removed from arr[1]
#  as we have set chars = None
print ("Output array: ", out_arr) 

输出：

Input array :  ['Sun' ' Moon ' 'Star']
Output array:  ['Sun' 'Moon' 'Star']

代码#2：

# Python program explaining
# numpy.char.lstrip() method 
  
import numpy as geek
  
# input arrays 
in_arr = geek.array([ 'Geeks', 'For', 'Geeks'] )
print ("Input array : ", in_arr) 
  
out_arr = geek.char.lstrip(in_arr, chars ='G')
  
# 'G' removed from arr[0] and arr[2]
# as we have set chars ='G'
print ("Output array: ", out_arr) 

输出：

Input array :  ['Geeks' 'For' 'Geeks']
Output array:  ['eeks' 'For' 'eeks']

代码#3：

# Python program explaining
# numpy.char.lstrip() method 
  
import numpy as geek
  
# input arrays 
in_arr = geek.array([ 'Geeks', 'For', 'Geeks'] )
print ("Input array : ", in_arr) 
  
out_arr = geek.char.lstrip(in_arr, chars ='s')
print ("Output array: ", out_arr) 
# Arrays remain unchanged as there are
# no strings which start with 's'

输出：

Input array :  ['Geeks' 'For' 'Geeks']
Output array:  ['Geeks' 'For' 'Geeks']