Python格式化字符串的简单方法

Python格式化字符串的简单方法

Python有三种格式化字符串的方式：

1. %-格式化
2. str.format()
3. f-Strings，超级好用

1. %-格式化

name = "北山啦"
age = 18

"%s. am %s years old " %(name, age)

2. str.format()

# 替换字段用大括号进行标记
"hello, {}. you are {}?".format(name,age)

'hello, hoxis. you are 18?'

• 可以通过索引来以其他顺序引用变量

"hello, {1}. you are {0}?".format(age,name)

'hello, hoxis. you are 18?'

# 使用key-value的键值对
"hello, {name}. you are {age1}?".format(age1=age,name=name)

'hello, hoxis. you are 18?'

# 直接从字典读取数据
person = {
    
    "name":"hoxis","age":18}
"hello, {name}. you are {age}?".format(**person)

'hello, hoxis. you are 18?'

# 依然会比较冗长
"hello, {}. you are {} ?. Your country is {}, and your hair is {}".format(name, age, country,hair)

'hello, hoxis. you are 18 ?. Your country is China, and your hair is black'

3. f-Strings

从Python3.6引入

# 以f字符开头，大括号直接使用变量
f"hi, {name}, are you {age}"

'hi, hoxis, are you 18'

# 直接在大括号里执行计算
f"{ 2 * 3 + 1}"

'7'

# 直接调用函数
test = lambda x : x.lower()
name = "Hoxis"
f"{test(name)} is handsome."

'hoxis is handsome.'

# 直接调用内置函数
f"{name.lower()} is handsome."

'hoxis is handsome.'

# 注意1：如果包含大括号，需要写多个
f"{
    
    {74}}"