f-string 格式化字符串的高级用法

data = {'name': 'Alice', 'age': 30, 'city': 'New York'}
print(f"User: {data['name']}, Age: {data['age']}, City: {data['city']}")

numbers = [1, 2, 3, 4, 5]
print(f"First number: {numbers[0]}, Last number: {numbers[-1]}")

data['name']

numbers[0]

x = 10
y = 5
print(f"The sum of {x} and {y} is {x + y}")
print(f"The product of {x} and {y} is {x * y}")

import math
radius = 5
print(f"The area of a circle with radius {radius} is {math.pi * radius**2:.2f}")

x + y

x * y

math.pi * radius**2

:.2f

score = 85
result = f"Pass: {score >= 60}"
print(result)

age = 15
status = f"You are {'eligible' if age >= 18 else 'not eligible'} to vote."
print(status)

{'eligible' if age >= 18 else 'not eligible'}

age

import datetime

now = datetime.datetime.now()
print(f"Today is {now:%Y-%m-%d %H:%M:%S}")

%Y-%m-%d %H:%M:%S

%Y

%m

%d

%H

%m

%S

=

x = 10
y = 5
print(f"{x=}, {y=}")
print(f"{x + y=}")

x=10, y=5
x + y=15

user_input = input("Enter an expression: ")
# 避免直接执行用户输入的表达式
# result = f"{user_input}" # 存在安全风险
# 应该对用户输入进行验证和过滤