OC操作字符串

//--------操作静态字符串--NSString----------------------------------------------------

NSString *Beijing= @"北京欢迎您";
//字符串的声明

NSString *log=@"北京欢迎您a"; //[NSString stringWithFormat:@"I am '%@'",Beijing];
//字符串格式化

NSString *zhui = [Beijing stringByAppendingString:@"哈哈哈"];
//字符串追加

bool b=[Beijing isEqualToString:log];
//字符串比较

NSString *hh = @"http://www.sina.com.cn";
if([hh hasPrefix:@"http"]){
//查找以http开头的字符串
        NSLog(@"含有http");
    }

else{
        NSLog(@"没有http");
}

NSString *ss = @"123";
int a = [ss intValue]+13;
//字符串转int型
double dd = [ss doubleValue]+33.3;
//字符串转double型
    NSLog(@"%g",dd);

//字符串转数组
NSString *zifuchuan = @"one,two,three,four";
    NSLog(@"string:%@",zifuchuan);
NSArray *array = [zifuchuan componentsSeparatedByString:@","];
//
NSLog(@"array:%@",array);
//输出整个数组中所有元素
NSString *value = [array objectAtIndex:0];
//取出第0个元素

NSLog(@"value:%@",value);
//数组转字符串
NSString *zifuchuan2 = [array componentsJoinedByString:@","];
NSLog(@"zifuchuan2:%@",zifuchuan2);

//-substringToIndex:
从字符串的开头一直截取到指定的位置，但不包括该位置的字符
NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringToIndex:3];
NSLog(@"string2:%@",string2);

//-substringFromIndex:
以指定位置开始（包括指定位置的字符），并包括之后的全部字符
NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringFromIndex:3];
NSLog(@"string2:%@",string2);

//-substringWithRange:
//按照所给出的位置，长度，任意地从字符串中截取子串
NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];
NSLog(@"string2:%@",string2);

//--------操作动态字符串--NSMutableString----------------------------------------------------

NSMutableString *mstr = [[NSMutableString alloc] init];

NSString *str1 = @"This is a example.";

//创建可变字符串
mstr = [NSMutableString stringWithString:str1];
//插入字符
[mstr insertString:@"very easy " atIndex:10];

//删除一些字符
[mstr deleteCharactersInRange:NSMakeRange(10,5)];

//查找并删除
NSRange substr = [mstr rangeOfString:@"example"];
//字符串查找,可以判断字符串中是否有
if (substr.location != NSNotFound)
{
[mstr deleteCharactersInRange:substr];
}

//重新设置字符串
[mstr setString:@"This is string AAA"];
//替换字符串
[mstr replaceCharactersInRange:NSMakeRange(15, 2) withString:@"BBB"];
//从第15个字符串处替换掉后2个字符串


//查找第一个并替换
NSString *search = @"This is";
NSString *replace = @"An example of";
substr = [mstr rangeOfString:search];
if (substr.location != NSNotFound)
{
[mstr replaceCharactersInRange:substrwithString:replace];
//把第1个遇到的substr替换为replace
        NSLog(@"%@",mstr);
    }


//查找全部匹配的，并替换
search = @"a";
replace = @"X";
substr = [mstr rangeOfString:search];
while (substr.location != NSNotFound) {
[mstr replaceCharactersInRange:substrwithString:replace];
substr = [mstr rangeOfString:search];
}

NSLog(@"%@",mstr);