Objective-C字符串NSString

遍历字符串

    NSString * str = @"YUOSOUCANG";

    int count = [str length];

    NSLog(@"%d",count);


    for (int i = 0; i < count; i++) {
        char c = [str characterAtIndex:i];

        NSLog(@"字符串的第%d位为%c",i,c);
    }

输出一些常见的变量

    int a = 1;
    double d = 2.2l;
    float f = 23.12;
    long l = 442;
    short s = 12;
    NSLog(@"a = %d, d = %e ,f = %f",a, d, f );

    bool a = NO;
    bool b = NO;
    NSString * str = @"fpc";

    if(a){
        NSLog(@"str = %@",str);
    }else{
        NSLog(@"str = %@",@"no");
    }

字符串的方法

    NSString * str0 = @"我是傅鹏程";

    NSString * str1 = [NSString stringWithFormat:@"我的名字：%@ 我的年龄 %d 我的邮箱 %s ",@"傅鹏程",23,"fpcfpc"];
    //把不同类型的值拼在一起

    NSLog(@"%@",str1);

    NSString * str3 = [str0 stringByAppendingString:str1];
    //字符串的拼接

    NSLog(@"%@",str3);

字符串的比较

    NSString * str0 = @"傅鹏程momo";

    NSString * str1 = @"傅鹏程momo";

    if ([str0 isEqualToString:str1]) {
        NSLog(@"相同");
    }

    if ([str0 hasPrefix:@"傅"]) {
        NSLog(@"开头");
    }

    if ([str0 hasSuffix:@"momo"]) {
        NSLog(@"结尾");
    }

字符串的截取方法

    NSString * stro = @"中文my name is 傅鹏程";

    NSString * to = [stro substringToIndex:4];
    //从起始位置到目标位置
    NSLog(@"to = %@",to);
    //to = 中文my


    NSString * from = [stro substringFromIndex:5];
    //从目标位置到结尾

    NSLog(@"from = %@", from);
    //from = name is 傅鹏程



    NSRange rang = NSMakeRange(3, 7);

    NSString * strRang = [stro substringWithRange:rang];
    //选取范围
    NSLog(@"strRang = %@",strRang);
    //strRang = y name



    //字符串的其他方法
    NSLog(@"字符串的首字母大写：%@",[[stro substringWithRange:rang] capitalizedString]);

    NSLog(@"把字符串都转成大写：%@",[stro uppercaseString]);

    NSLog(@"把字符串都转成小写：%@",[stro lowercaseString]);


//    2017-10-12 09:12:40.761 app1[1670:75841] to = 中文my
//    2017-10-12 09:12:40.761 app1[1670:75841] from = name is 傅鹏程
//    2017-10-12 09:12:40.761 app1[1670:75841] strRang = y name
//    2017-10-12 09:12:40.762 app1[1670:75841] 字符串的首字母大写：Y Name
//    2017-10-12 09:12:40.762 app1[1670:75841] 把字符串都转成大写：中文MY NAME IS 傅鹏程
//    2017-10-12 09:12:40.762 app1[1670:75841] 把字符串都转成小写：中文my name is 傅鹏程

字符串的搜索与替换

    NSString * str0 = @"中文my name is fupengcheng";

    NSString * temp = @"is";

    NSRange rang = [str0 rangeOfString:temp];

    NSLog(@"搜索到的字符串的起始位置: %d", rang.location);

    NSLog(@"搜索到的字符串的结束位置：%d", rang.location + rang.length);


    NSString * str1 = [str0 stringByReplacingCharactersInRange:rang withString:@"傅鹏程"];

    NSLog(@"替换后的字符串为:%@",str1);


    str1 = [str0 stringByReplacingOccurrencesOfString:@" " withString:@"@"];

    NSLog(@"替换后的字符串为:%@",str1);


//    2017-10-12 09:29:07.304 app1[1851:84555] 搜索到的字符串的起始位置: 10
//    2017-10-12 09:29:07.304 app1[1851:84555] 搜索到的字符串的结束位置：12
//    2017-10-12 09:29:07.304 app1[1851:84555] 替换后的字符串为:中文my name 傅鹏程 fupengcheng
//    2017-10-12 09:29:07.304 app1[1851:84555] 替换后的字符串为:中文my@name@is@fupengcheng