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Python 字符串格式化

Python基础 2022-06-06 12:54:34小码哥的IT人生shichen

Python 字符串格式化

为了确保字符串按预期显示,我们可以使用 format() 方法对结果进行格式化。

字符串 format()

format() 方法允许您格式化字符串的选定部分。

有时文本的一部分是你无法控制的,也许它们来自数据库或用户输入?

要控制此类值,请在文本中添加占位符(花括号 {}),然后通过 format() 方法运行值:

示例代码:

添加要显示价格的占位符:

price = 52
txt = "The price is {} dollars"
print(txt.format(price))

完整实例:

price = 52
txt = "The price is {} dollars"
print(txt.format(price))

您可以在花括号内添加参数以指定如何转换值:

示例代码:

将价格格式化为带有两位小数的数字:

txt = "The price is {:.2f} dollars"

完整实例:

price = 52
txt = "The price is {:.2f} dollars"
print(txt.format(price))

查看字符串 format() 参考手册中的所有格式类型。

多个值

如需使用更多值,只需向 format() 方法添加更多值:

print(txt.format(price, itemno, count))

并添加更多占位符:

示例代码:

quantity = 3
itemno = 567
price = 52
myorder = "I want {} pieces of item number {} for {:.2f} dollars."
print(myorder.format(quantity, itemno, price))

完整实例:

quantity = 3
itemno = 567
price = 52
myorder = "I want {} pieces of item number {} for {:.2f} dollars."
print(myorder.format(quantity, itemno, price))

索引号

您可以使用索引号(花括号 {0} 内的数字)来确保将值放在正确的占位符中:

示例代码:

quantity = 3
itemno = 567
price = 52
myorder = "I want {0} pieces of item number {1} for {2:.2f} dollars."
print(myorder.format(quantity, itemno, price))

完整实例:

quantity = 3
itemno = 567
price = 52
myorder = "I want {0} pieces of item number {1} for {2:.2f} dollars."
print(myorder.format(quantity, itemno, price))

此外,如果要多次引用相同的值,请使用索引号:

示例代码:

age = 63
name = "Bill"
txt = "His name is {1}. {1} is {0} years old."
print(txt.format(age, name))

完整实例:

age = 63
name = "Bill"
txt = "His name is {1}. {1} is {0} years old."
print(txt.format(age, name))

命名索引

您还可以通过在花括号 {carname} 中输入名称来使用命名索引,但是在传递参数值 txt.format(carname = "Ford") 时,必须使用名称:

示例代码:

myorder = "I have a {carname}, it is a {model}."
print(myorder.format(carname = "Porsche", model = "911"))

完整实例:

myorder = "I have a {carname}, it is a {model}."
print(myorder.format(carname = "Porsche", model = "911"))

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