pragma mark NSMutableString练习

pragma mark 概念

/**
字符串 拼接 (stringByAppendingString)
删除字符串的指定范围 并且以什么代替 (stringByReplacingCharactersInRange:withString)
去除字符串的首尾字符  (stringByTrimmingCharactersInSet) 空格等
删除一个范围 (deleteCharactersInRange)
 */

pragma mark 代码

#import <Foundation/Foundation.h>
#pragma mark 类

#pragma mark main函数
int main(int argc, const char * argv[])
{
#pragma mark NSMutableString练习
    /**
     需求: 将3个520lyh 拼接在一起, 中间用空格隔开
     520lyh 520lyh 520lyh
     */
#warning 1.不可变字符串 拼接
    /*
    NSString *subStr = @"520lyh";
    // 520lyh
    NSString *newStr = [subStr stringByAppendingString:@" "];
    // 520lyh 520lyh
    newStr = [newStr stringByAppendingString:subStr];

    // 520lyh  520lyh_
    newStr = [newStr stringByAppendingString:@" "];
    // 520lyh 520lyh 520lyh
    newStr = [newStr stringByAppendingString:subStr];
    NSLog(@"newStr = |%@|",newStr);
    newStr = nil;
    */
#warning 1.1 循环 不可变字符串 拼接
    NSString *subStr = @"520lyh";
    NSString *newStr = [subStr stringByAppendingString:@" "];
//    NSString *newStr = [subStr stringByAppendingString:@" "];
    // 循环操作
#warning －－ 注意⚠️: 在开发中 如果需要对字符串进行频繁的操作,不要使用不可变的字符串
    for (int i = 0; i < 2; ++i) {
        // 520lyh 520lyh
        newStr = [newStr stringByAppendingString:subStr];
        newStr = [newStr stringByAppendingString:@" "];
    }
#warning 2.删除字符串的指定范围 (删除最后一个 获取长度-1) (stringByReplacingCharactersInRange:withString)
//    newStr = [newStr stringByReplacingCharactersInRange:NSMakeRange(newStr.length - 1, 1) withString:@""];
    newStr = [newStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]; // 这里只会去除末尾的空格
    NSLog(@"newStr = |%@|",newStr);

#pragma mark 可变字符串
#warning 3.可变字符串
    subStr = @"520lyh";
    NSMutableString *strM = [NSMutableString string];
    for (int i = 0; i < 3; ++i)
    {
        // 1. 添加一个520lyh
        [strM appendString:subStr];
        // 2.添加一个空格
        [strM appendString:@" "];
    }
#warning 4.删除一个范围 (deleteCharactersInRange)
    [strM deleteCharactersInRange:NSMakeRange(strM.length - 1, 1)];
    NSLog(@"strM = |%@|",strM);

    
    return 0;
}