Python 字符串转换方法

maketrans()

maketrans()方法返回一个映射表。它将astr中的每个字符映射到bstr中相同索引位置的字符。该方法返回的映射表可以被translate()方法使用来替换字符。

语法

var.maketrans(astr, bstr, cstr)

参数

astr − 这可以是字典或字符串。如果只提供一个参数，则此参数必须是字典。如果提供两个或多个参数，则此参数必须是一个指定要替换的字符的字符串。
bstr − 这是具有相应映射字符的字符串。
cstr − 可选。字符串参数指定要从字符串中删除的字符。

返回值

此方法返回一个用于translate()函数的转换表。

示例

var = 'Explicit is better than implicit.'
table = var.maketrans({'i':'I'})
print ("original string:", var)
print ("translation table:", table)

var1 = var.translate(table)
print ("Translated string", var1)

var = "Explicit is better than implicit."
table = var.maketrans("than", "then")
print ("original string:", var)
print ("translation table:", table)
var2 = var.translate(table)
print ("Translated string", var2)

var = 'Explicit is better than implicit.'
table = var.maketrans("is","as", "s")
print ("original string:", var)
print ("translation table:", table)
var3=var.translate(table)
print ("Translated string", var3)

运行此程序时，将会产生以下输出 –

original string: Explicit is better than implicit.
translation table: {105: 'I'}
Translated string ExplIcIt Is better than ImplIcIt.
original string: Explicit is better than implicit.
translation table: {116: 116, 104: 104, 97: 101, 110: 110}
Translated string Explicit is better then implicit.
original string: Explicit is better than implicit.
translation table: {105: 97, 115: None}
Translated string Explacat a better than amplacat.

translate()

translate()方法返回一个字符串，其中每个字符都被其对应的字符在maketrans()方法创建的转换表中替换。

语法

var.translate(table)

参数

table − 由maketrans ()方法创建的转换表。

返回值

此方法返回字符串的转换副本。

示例

var = 'Explicit is better than implicit.'
table = var.maketrans({'i':'I'})
print ("original string:", var)
print ("translation table:", table)

var1 = var.translate(table)
print ("Translated string", var1)

var = "Explicit is better than implicit."
table = var.maketrans("than", "then")
print ("original string:", var)
print ("translation table:", table)
var2 = var.translate(table)
print ("Translated string", var2)

var = 'Explicit is better than implicit.'
table = var.maketrans("is","as", "s")
print ("original string:", var)
print ("translation table:", table)
var3=var.translate(table)
print ("Translated string", var3)

运行此程序时，它将产生以下输出 −

original string: Explicit is better than implicit.
translation table: {105: 'I'}
Translated string ExplIcIt Is better than ImplIcIt.
original string: Explicit is better than implicit.
translation table: {116: 116, 104: 104, 97: 101, 110: 110}
Translated string Explicit is better then implicit.
original string: Explicit is better than implicit.
translation table: {105: 97, 115: None}
Translated string Explacat a better than amplacat.