python中格式化字符串的几种方法

# 方法1: 使用 % 操作符 (旧式格式化)
name = "Alice"
age = 30
formatted_string = "My name is %s and I am %d years old." % (name, age)
print(formatted_string)  # 输出: My name is Alice and I am 30 years old.

# 方法2: 使用 str.format() 方法 (新式格式化)
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.

# 方法3: 使用命名参数
formatted_string = "My name is {n} and I am {a} years old.".format(n=name, a=age)
print(formatted_string)  # 输出: My name is Alice and I am 30 years old.

# 方法4: 使用 f-string (Python 3.6+)
formatted_string = f"My name is {name} and I am {age} years old."
print(formatted_string)  # 输出: My name is Alice and I am 30 years old.

# 方法5: 使用 format 函数与索引
formatted_string = "My name is {0} and I am {1} years old.".format(name, age)
print(formatted_string)  # 输出: My name is Alice and I am 30 years old.