Python中的字符串切割和拼接方法有哪些？

str1 = "Hello, World!"
parts = str1.split(",")   # 使用逗号进行切割
print(parts)   # 输出：['Hello', ' World!']

parts = ['Hello', 'World!']
str1 = ", ".join(parts)   # 使用逗号和空格进行拼接
print(str1)   # 输出：Hello, World!

str1 = "Hello, World!"
part1 = str1[:5]   # 切割前五个字符
part2 = str1[7:]   # 从第七个字符开始切割
print(part1)   # 输出：Hello
print(part2)   # 输出：World!

str1 = "Hello"
str2 = "World!"
str3 = str1 + ", " + str2   # 使用加号进行拼接
print(str3)   # 输出：Hello, World!

name = "John"
age = 25
str1 = "My name is {} and I am {} years old.".format(name, age)
print(str1)   # 输出：My name is John and I am 25 years old.

name = "John"
age = 25
str1 = f"My name is {name} and I am {age} years old."
print(str1)   # 输出：My name is John and I am 25 years old.