1. The syntax and usage of the replace function

(1) Syntax: str.replace(old_str,new_str[,max_num])

old_str: Mandatory, the old string is the target string to be replaced.

new_str: Mandatory, the new string is the target string to be converted.

max_num: optional, specifies the number of substitutions. If not filled, the default is infinite.

(2) Usage: Replace the specified string with the target string.

kips: The replace function is mainly used in a field column to replace strings with certain rules.

2. Examples

(1) Simple usage

#①
string='Hello Amy,welcome to our world'
new_string = string.replace('our','my')
new_string
#输出结果：'Hello Amy,welcome to my world'

#②
string1='Hello Amy,welcome to my world,your world,his world,her world,our world'
new_string1 = string1.replace('world','place')
new_string1
#输出结果：'Hello Amy,welcome to my place,your place,his place,her place,our place'


#③
string2='Hello Amy,welcome to my world,your world,his world,her world,our world'
new_string2 = string1.replace('world','place',4)
new_string2
#输出结果：'Hello Amy,welcome to my place,your place,his place,her place,our world'

#解释：①和②例子第三个参数默认为无数个，即可以替代无数个，③设置次数表示只能替代4个

(2) Combined with some functions

①Used in combination with the input function

old_str = 'I'
new_str = 'all'
string = input('请输入需要调整的字符串：')
new_string = string.replace(old_str,new_str)
print(new_string)

#iput：
'Forever young,I want to be forever young.Forever young,I want to be forever young.So many dreams swinging out of blue.We let them come true.'

#output：
'Forever young,all want to be forever young.Forever young,all want to be forever young.So many dreams swinging out of blue.We let them come true.'

②Use in combination with input function and if function

old_str = 'I'
new_str = 'all'
string = input('请输入需要调整的字符串：')
if 'I' in string:
    new_string = string.replace(old_str, new_str)
    print(new_string)
elif 'We'in string:
    new_string = string.replace('We', 'all of us')
    print(new_string)
else:
     new_string = string.replace('We', 'I')
     print(new_string)



#input：
请输入需要调整的字符串：'Forever young,I want to be forever young.Forever young,I want to be forever young.So many dreams swinging out of blue.We let them come true.'

#output:
'Forever young,all want to be forever young.Forever young,all want to be forever young.So many dreams swinging out of blue.We let them come true.'

③Use in combination with input function, while function and if function

old_str = 'I'
new_str = 'all'
while True:
    string = input('请输入需要调整的字符串：')
    if 'I' in string:
        new_string = string.replace(old_str, new_str)
        print(new_string)
    elif 'We'in string:
        new_string = string.replace('We', 'all of us')
        print(new_string)
    else:
         new_string = string.replace('We', 'I')
         print(new_string)

#①第一个循环
请输入需要调整的字符串：'Forever young,I want to be forever young.Forever young,I want to be forever young.So many dreams swinging out of blue.We let them come true.'
#输出结果为：
'Forever young,all want to be forever young.Forever young,all want to be forever young.So many dreams swinging out of blue.We let them come true.'


#②第二个循环
请输入需要调整的字符串：'I want to go into your heart,let me live into there'
#输出结果：
'all want to go into your heart,let me live into there'
请输入需要调整的字符串：

#一直循环输入。。。。

reference article

For specific usage of the input function, please refer to the article: Usage of input function in python

For specific usage of if judgment statement, please refer to: Usage and examples of python's if conditional statement

Other articles: Python replace() method | rookie tutorial (runoob.com)

How does python implement the usage and examples of string replacement replace function