Python 用新字符串替换子字符串的所有出现

在本文中，我们将实现各种示例，用新字符串替换子字符串的所有出现。假设我们有以下字符串-

Hi, How are you? How have you been?

我们必须将子字符串”How “的所有出现替换为”Demo”。 因此，输出应为−

Hi, Demo are you? Demo have you been?

现在让我们来看一些示例

使用replace()函数将Python子字符串的所有出现替换为新字符串

示例

在这个示例中，我们将使用replace()函数来替换Python子字符串的所有出现为新字符串-

# String
myStr = "Hi, How are you? How have you been?"

# Display the String
print("String = " + myStr)

# Replacing and returning a new string
strRes = myStr.replace("How", "Demo")

# Displaying the Result
print("Result = " + strRes)

输出

String = Hi, How are you? How have you been?
Result = Hi, Demo are you? Demo have you been?

使用正则表达式sub()函数替换子字符串的出现

假设您想要替换不同的子字符串。为此，我们可以使用正则表达式。在下面的示例中，我们将不同的子字符串”What”和”How”替换为”Demo”。

首先，在Python中安装re模块以使用正则表达式-

pip install re

然后，导入re模块

import re

以下是完整的代码

import re
# String
myStr = "Hi, How are you? What are you doing here?"

# Display the String
print("String = " + myStr)

# Replacing and returning a new string
strRes = re.sub(r'(How|What)', 'Demo', myStr)

# Displaying the Result
print("Result = " + strRes)

输出

String = Hi, How are you? What are you doing here?
Result = Hi, Demo are you? Demo are you doing here?

使用模式对象将Python子字符串的出现替换为新字符串

示例

以下是代码 –

import re
# String
myStr1 = "Hi, How are you?"
myStr2 = "What are you doing here?"

# Display the String
print("String1 = " + myStr1)
print("String2 = " + myStr2)

# Replacing with Pattern Objects
pattern = re.compile(r'(How|What)')
strRes1 = pattern.sub("Demo", myStr1)
strRes2 = pattern.sub("Sample", myStr2)

# Displaying the Result
print("\nResult (string1) = " + strRes1)
print("Result (string2) = " + strRes2)

输出

String1 = Hi, How are you?
String2 = What are you doing here?
Result (string1) = Hi, Demo are you?
Result (string2) = Sample are you doing here?