如何在Python中处理字符串操作的问题

str1 = "Hello"
str2 = "World"
result = str1 + " " + str2
print(result)  # 输出：Hello World

name = "Tom"
age = 25
result = "My name is %s, and I'm %d years old." % (name, age)
print(result)  # 输出：My name is Tom, and I'm 25 years old.

name = "Tom"
age = 25
result = "My name is {}, and I'm {} years old.".format(name, age)
print(result)  # 输出：My name is Tom, and I'm 25 years old.

name = "Tom"
age = 25
result = f"My name is {name}, and I'm {age} years old."
print(result)  # 输出：My name is Tom, and I'm 25 years old.

str1 = "Hello"
print(str1[0])  # 输出：H
print(str1[-1])  # 输出：o

str1 = "Hello World"
print(str1[6:11])  # 输出：World
print(str1[2:])  # 输出：llo World
print(str1[:5])  # 输出：Hello
print(str1[::-1])  # 输出：dlroW olleH

str1 = "Hello World"
print(str1.find("o"))  # 输出：4
print(str1.find("abc"))  # 输出：-1（表示未找到）

str1 = "Hello World"
result = str1.replace("World", "Python")
print(result)  # 输出：Hello Python

str1 = "Hello"
print(str1.isalpha())  # 输出：True
str2 = "Hello123"
print(str2.isalpha())  # 输出：False

str1 = "123"
print(str1.isdigit())  # 输出：True
str2 = "Hello123"
print(str2.isdigit())  # 输出：False

str1 = "Hello"
print(str1.lower())  # 输出：hello
str2 = "WORLD"
print(str2.upper())  # 输出：WORLD

str1 = "Hello World"
result = str1.split()
print(result)  # 输出：['Hello', 'World']

strs = ['Hello', 'World']
result = " ".join(strs)
print(result)  # 输出：Hello World