iOS开发 NSString字符串操作

    NSString *content = @"<phone>12345678963</phone><address>78945612333</address>";
        NSRange str = [content rangeOfString:@"<address>"];
             
        
        //截取固定部分
        NSString *substr = [content substringWithRange:str];
        NSLog(@"address is %@",substr);
        
        // 拼接文件夹用 ／
        NSString *try1 = [substr stringByAppendingPathComponent:content];
        NSLog(@"try 1 = %@",try1);
        
        // 拼接文件夹用 .
        NSString *try2 = [content stringByAppendingPathExtension:substr];
        NSLog(@"try 2 = %@",try2);
        
        // 截取从选定位置开始 并指定长度
        NSString *try3 = [content substringWithRange:NSMakeRange(str.location, 20)];
        NSLog(@"try3 = %@",try3);
        
        NSArray *try4 = [content componentsSeparatedByString:@">"];
        NSLog(@"try4 = %@",try4);
        
        // 从指定位置开始截取
        NSRange range1 = NSMakeRange(str.location, str.length);        
        NSString *try5 = [content substringFromIndex:range1.location +range1.length];
        NSLog(@"try5 = %@",try5);
        
        //截取到指定位置
        NSRange str1 = [try5 rangeOfString:@"</address>"];
        NSRange range2 = NSMakeRange(str1.location, str1.length);
        NSString *try6 = [try5 substringToIndex:range2.location];
        NSLog(@"try6 = %@",try6);
        
//设置字符串首字母大写
     NSLog(@"str0首字母大写:%@",[str0 capitalizedString]);
     //设置字符串全部内容为大写
     NSLog(@"str0大写:%@",[str0 uppercaseString]);
     //设置字符全部内容为小写
     NSLog(@"str0小写:%@",[str0 lowercaseString]);

//搜索查找

NSRange range = [str rangeOfString:@"345"];

if (range.location == NSNotFound) {

    //没有找到

}


//截取
从第3个开始到之后的
[str substringFromIndex:3];
截取到第5个
[str substringToIndex:5];
从第2个开始 截取4个
[str substringWithRange:NSMakeRange(2, 4)];

// 关于大小写的转化
//字符串转换
NSString *str=@"abc";
NSString *str=@"ABC";
NSLog(@"uppercase:%@",[str uppercaseString]);//打印出ABC
NSLog(@"lowercase:%@",[stri lowercaseString]);//打印出abc

字符串转化
NSString *str = @"100";

//转int

int a = [str intValue];

//算字数

int len = [str length];

//取字符

unichar c = [str characterAtIndex:0];

//返回c语言的字符串

char *s = [str UTF8String];

 

除了NSString，还有一个NSMutableString是可变字符串，是NSString的子类。

NSMutableString *str = [[NSMutableString alloc] initWithCapacity:8];

[str setString:@"1234"];
拼接
[str appendString:@"567890"];
替换
[str replaceCharactersInRange:[str rangeOfString:@"456"] withString:@"xxx"];
插入
[str insertString:@"yyy" atIndex:6];
删除
[str deleteCharactersInRange:[str rangeOfString:@"xxyy"]];

NSLog(@"%@", str);