Python格式化字符串的四种常见方式

# 定义变量
name = "Alice"
age = 25
# 使用 % 格式化字符串，%s 表示字符串类型，%d 表示整数类型
message = "My name is %s and I am %d years old." % (name, age)
print(message)  # 输出格式化后的字符串

# 格式化浮点数，%.2f 表示保留两位小数
height = 1.65
height_message = "My height is %.2f meters." % height
print(height_message)

# 定义变量
name = "Bob"
age = 30
# 使用 str.format() 方法格式化字符串
message = "My name is {} and I am {} years old.".format(name, age)
print(message)

# 通过索引指定占位符的填充顺序
message_index = "My name is {1} and I am {0} years old.".format(age, name)
print(message_index)

# 通过关键字参数指定占位符的填充
message_keyword = "My name is {name} and I am {age} years old.".format(name=name, age=age)
print(message_keyword)

# 格式化浮点数，指定保留小数位数
weight = 70.5
weight_message = "My weight is {:.1f} kilograms.".format(weight)
print(weight_message)

# 定义变量
name = "Charlie"
age = 35
# 使用 f-string 格式化字符串
message = f"My name is {name} and I am {age} years old."
print(message)

# 在 f-string 中使用表达式
birth_year = 2023 - age
message_expr = f"I was born in {birth_year}."
print(message_expr)

# 格式化浮点数
salary = 5000.75
salary_message = f"My monthly salary is {salary:.2f} yuan."
print(salary_message)

from string import Template

# 定义变量
name = "David"
age = 40
# 创建模板字符串
template = Template("My name is $name and I am $age years old.")
# 使用 substitute() 方法替换占位符
message = template.substitute(name=name, age=age)
print(message)