python之字符串定义、切片、连接、重复、遍历、字符串方法

 # 字符串定义
    str = "hello"
    str2 = 'world'
    str3 = "hi 'tom'"
    # hello world hi 'tom'
    print(str, str2, str3)

  # 字符串长度和索引
    greet = "Hello Bob"
    # 10
    print(len(greet))
    # 索引访问 H b
    print(greet[0], greet[-1])
    # 切片
    # Helllo Bob
    print(greet[:])
    # e
    print(greet[1:2])
    # Hello
    print(greet[:5])
    # Bob
    print(greet[5:])

     # 字符串长度和索引
    greet = "Hello Bob" 
    # +连接 Hello BobHello Bob
    print(greet + greet)
    # *重复 Hello BobHello BobHello BobHello BobHello Bob
    print(greet * 5)
    # 遍历 H e l l o   B o b
    for ch in greet:
        print(ch,end=" ")

    #     a 的ASCII
    print(ord("a"))
    # ASCII对应的字母
    print(chr(97))
    str="hello, I came here for an argument"
    # 第一个字母大写 Hello, i came here for an argument
    print(str.capitalize())
    # 每个单词的第一个字母大写  Hello, I Came Here For An Argument
    print(str.title())
    # 所有单单词小写 hello, i came here for an argument
    print(str.lower())
    # 所有单次大写 HELLO, I CAME HERE FOR AN ARGUMENT
    print(str.upper())
    # 替换hello, you came here for an argument
    print(str.replace("I","you"))
    # 在给定宽度60中居中显示str
    print(str.center(60))
    # 统计o出现的次数 2
    print(str.count('o'))
    # o第一次出现的位置 4
    print(str.find("o"))
    # 列表连接成字符串，使用，分割 a，b，c
    print("，".join(["a","b","c"]))

if __name__ == '__main__':
    # 字符串定义
    str = "hello"
    str2 = 'world'
    str3 = "hi 'tom'"
    # hello world hi 'tom'
    print(str, str2, str3)
    # 字符串长度和索引
    greet = "Hello Bob"
    # 10
    print(len(greet))
    # 索引访问 H b
    print(greet[0], greet[-1])
    # 切片
    # Helllo Bob
    print(greet[:])
    # e
    print(greet[1:2])
    # Hello
    print(greet[:5])
    # Bob
    print(greet[5:])
    # +连接 Hello BobHello Bob
    print(greet + greet)
    # *重复 Hello BobHello BobHello BobHello BobHello Bob
    print(greet * 5)
    # 遍历 H e l l o   B o b
    for ch in greet:
        print(ch,end=" ")
    #     a 的ASCII
    print(ord("a"))
    # ASCII对应的字母
    print(chr(97))
    str="hello, I came here for an argument"
    # 第一个字母大写 Hello, i came here for an argument
    print(str.capitalize())
    # 每个单词的第一个字母大写  Hello, I Came Here For An Argument
    print(str.title())
    # 所有单单词小写 hello, i came here for an argument
    print(str.lower())
    # 所有单次大写 HELLO, I CAME HERE FOR AN ARGUMENT
    print(str.upper())
    # 替换hello, you came here for an argument
    print(str.replace("I","you"))
    # 在给定宽度60中居中显示str
    print(str.center(60))
    # 统计o出现的次数 2
    print(str.count('o'))
    # o第一次出现的位置 4
    print(str.find("o"))
    # 列表连接成字符串，使用，分割 a，b，c
    print("，".join(["a","b","c"]))