python语言format用法

# 示例代码：使用 format 方法进行字符串格式化

# 基本用法：位置参数
name = "Alice"
age = 30
formatted_string = "My name is {} and I am {} years old.".format(name, age)
print(formatted_string)  # 输出: My name is Alice and I am 30 years old.

# 指定索引：通过索引指定参数位置
formatted_string = "My name is {1} and I am {0} years old.".format(age, name)
print(formatted_string)  # 输出: My name is Alice and I am 30 years old.

# 命名参数：通过名称指定参数
formatted_string = "My name is {name} and I am {age} years old.".format(name="Alice", age=30)
print(formatted_string)  # 输出: My name is Alice and I am 30 years old.

# 格式化数字：指定小数点后位数
pi = 3.141592653589793
formatted_string = "The value of pi is {:.2f}".format(pi)
print(formatted_string)  # 输出: The value of pi is 3.14

# 对齐和填充：> 左对齐，< 右对齐，^ 居中对齐
formatted_string = "{:<10} is left aligned".format("left")
print(formatted_string)  # 输出: left       is left aligned

formatted_string = "{:>10} is right aligned".format("right")
print(formatted_string)  # 输出:      right is right aligned

formatted_string = "{:^10} is centered".format("center")
print(formatted_string)  # 输出:   center    is centered