python字符串格式化方式解析

Python  /  管理员 发布于 7年前   155

1.%格式符

name = '李四'age = 18a = "姓名:%s,年龄:%s"%(name,age)print(a)   #姓名:李四,年龄:18​b = "%(name)s,%(age)s"%{'name':'张三','age':18}print(b)   #张三,18

这种格式化并不是很好，因为它很冗长并且容易导致错误，比如没有正确显示元组或字典

2.str.format()

name = '李四'age = 18# 替换字段用大括号进行标记a1 = "hello, {}. you are {}?".format(name,age)print(a1)   #hello, 李四. you are 18?​# 通过索引来以其他顺序引用变量a2 = "hello, {1}. you are {0}?".format(age,name)print(a2)  #hello, 李四. you are 18?​# 通过参数来以其他顺序引用变量a3 = "hello, {name}. you are {age1}?".format(age1=age,name=name)print(a3)  #hello, 李四. you are 18?​# 从字典中读取数据时还可以使用 **data = {"name":"张三","age":18}a4 = "hello, {name}. you are {age}?".format(**data)print(a4)  #hello, 李四. you are 18?

在处理多个参数和更长的字符串时仍然可能非常冗长

3.f-Strings

f-strings 是指以 f 或 F 开头的字符串，其中以 {} 包含的表达式会进行值替换。

name = '李四'age = 18# F 和 f 的简单使用b1 = f"hello, {name}. you are {age}?"b2 = F"hello, {name}. you are {age}?"print(b1)   # hello, 李四. you are 18?print(b2)   # hello, 李四. you are 18?# 字典也可以teacher = {'name': 'meet', 'age': 18}msg = f"The teacher is {teacher['name']}, aged {teacher['age']}"print(msg) # The comedian is meet, aged 18# 列表也行l1 = ['meet', 18]msg = f'姓名：{l1[0]},年龄：{l1[1]}.'print(msg) # 姓名：meet,年龄：18.#可以插入表达式def sum_a_b(a,b):  return a + ba = 1b = 2print('求和的结果为' + f'{sum_a_b(a,b)}')#多行f 反斜杠name = 'barry'age = 18ajd = 'handsome'speaker = f'Hi {name}.'\     f'You are {age} years old.'\     f'You are a {ajd} guy!'print(speaker)  #Hi barry.You are 18 years old.You are a handsome guy!print(f"{You are very \"handsome\"}")   #报错#括号的处理 -->重点：两对为一组print(f"{{73}}") # {73}print(f"{{{73}}}") # {73}print(f"{{{{73}}}}") # {{73}}m = 21# ! , : { } ;这些标点不能出现在{} 这里面。# print(f'{;12}') # 报错# 所以使用lambda 表达式会出现一些问题。# 解决方式：可将lambda嵌套在圆括号里面解决此问题。x = 5print(f'{(lambda x: x*2) (x)}') # 10

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