Python中格式化的字符串文字（f字符串）？
Python现在提供了一种格式化字符串的新方法，称为f字符串。可从PEP-498下的Python3.6获得此功能。它们之所以称为(f-string)，是因为带有字符串的字母'f'前缀。字母“f”还表示这些f字符串可用于格式化。
下面是一些示例，用于演示f字符串的用法。
程式#1
name = 'Rajesh'
age = 13 * 3
fString = f'My name is {name} and my age is {age}'
print(fString)
#We can use Uppercase 'F' instead of lowercase 'f'.
print(F'My name is {name} and my age is {age}')
#As the fString valuation is done, giving another value to the variable will not change fstring value.
name = 'Zack'
age = 44
print(fString)输出结果
My name is Rajesh and my age is 39 My name is Rajesh and my age is 39 My name is Rajesh and my age is 39
Example#2–带表达式和转换的f字符串
从datetime导入datetime
name = 'Rajesh'
age = 13 * 3
dt = datetime.now()
print(f' Age after ten years will be {age + 10}')
print(f'Name with quotes = {name!r}')
print(f'Default formatted Date = {dt}')
print(f'Modified Date format = {dt: %d/%m/%Y}')输出结果
Age after ten years will be 49 Name with quotes = 'Rajesh' Default formatted Date = 2019-02-11 14:52:05.307841 Modified Date format = 11/02/2019
Example#3：对象和属性
class Vehicle:
Model = 0
Brand = ''
def __init__(self, Model, Brand):
self.Model = Model
self.Brand = Brand
def __str__(self):
return f'E[Model={self.Model}, Brand = {self.Brand}]'
Car = Vehicle (2018, 'Maruti')
print(Car)
print(f'Vehicle: {Car}\nModel is {Car.Model} and Brand is {Car.Brand}')输出结果
E[Model=2018, Brand = Maruti] Vehicle: E[Model=2018, Brand = Maruti] Model is 2018 and Brand is Maruti
Example#4：调用函数
我们也可以用f字符串格式调用函数。
def Multiply(x,y):
return x*y
print( f'Multiply(40,20) = {Multiply(40,20)}')输出结果
Multiply(40,20) = 800
Example#5：Lambda表达式
x = -40.9
print(f' Lambda absolute of (-40.9) is : {(lambda x: abs(x)) (x)}')
print(f' Lambda Square of 2^4 is: {(lambda x: pow(x, 2)) (4)}')输出结果
Lambda absolute of (-40.9) is : 40.9 Lambda Square of 24 is: 16