如何用新字符串替换 Python 子字符串的所有出现？

在本文中，我们将实现各种示例来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?

我们必须将所有“How ”子字符串替换为“Demo”。因此，输出应为 −

Hi, Demo are you? Demo have you been?

现在让我们看一些示例 −

使用 replace() 方法替换 Python 子字符串的所有出现

示例

在本例中，我们将使用 replace() 方法将 Python 子字符串的所有出现替换为新字符串：

Open Compiler
# 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() 替换子字符串的出现

假设您想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，安装 re 模块以在 Python 中使用正则表达式：

pip install re

然后，导入 re 模块 −

import re

以下是完整的代码：

Open Compiler
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?

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使用模式对象替换 Python 子字符串的出现

示例

以下是代码 −

Open Compiler
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?

更新于: 2022-09-15

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