How to remove unwanted characters from a string in Python

This article mainly introduces in detail how Python removes unwanted characters from strings. It has certain reference value. Interested friends can refer to it.

Question:

Filter the extra white space characters before and after the user input

Filter the '\r' in the edit text under a certain windows:

#How to solve the above problems?

Remove strings at both ends: strip(), rstrip(),lstrip()

#!/usr/bin/python3
 
s = ' -----abc123++++  '
 
# 删除两边空字符
print(s.strip())
 
# 删除左边空字符
print(s.rstrip())
 
# 删除右边空字符
print(s.lstrip())
 
# 删除两边 - + 和空字符
print(s.strip().strip('-+'))

Delete a single fixed position character : Slicing and splicing

#!/usr/bin/python3
 
s = 'abc:123'
# 字符串拼接方式去除冒号
new_s = s[:3] + s[4:]
print(new_s)

Delete characters at any position and delete multiple different characters at the same time: replace(), re.sub()

#!/usr/bin/python3
 
# 去除字符串中相同的字符
s = '\tabc\t123\tisk'
print(s.replace('\t', ''))
 
 
import re
# 去除\r\n\t字符
s = '\r\nabc\t123\nxyz'
print(re.sub('[\r\n\t]', '', s))

Delete multiple different characters at the same time: translate()   Map str.maketrans() in py3

#!/usr/bin/python3
 
s = 'abc123xyz'
# a _> x, b_> y, c_> z，字符映射加密
print(str.maketrans('abcxyz', 'xyzabc'))
# translate把其转换成字符串
print(s.translate(str.maketrans('abcxyz', 'xyzabc')))

Remove the tones in unicode characters

#!/usr/bin/python3
 
import sys
import unicodedata
s = "Zhào Qián Sūn Lǐ Zhōu Wú Zhèng Wáng"
remap = {
 # ord返回ascii值
 ord('\t'): '',
 ord('\f'): '',
 ord('\r'): None
 }
# 去除\t, \f, \r
a = s.translate(remap)
'''
　　通过使用dict.fromkeys() 方法构造一个字典，每个Unicode 和音符作为键，对于的值全部为None
　　然后使用unicodedata.normalize() 将原始输入标准化为分解形式字符
　　sys.maxunicode : 给出最大Unicode代码点的值的整数，即1114111（十六进制的0x10FFFF）。
　　unicodedata.combining:将分配给字符chr的规范组合类作为整数返回。 如果未定义组合类，则返回0。
'''
cmb_chrs = dict.fromkeys(c for c in range(sys.maxunicode) if unicodedata.combining(chr(c))) #此部分建议拆分开来理解
b = unicodedata.normalize('NFD', a)
'''
　　　调用translate 函数删除所有重音符
'''
print(b.translate(cmb_chrs))

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