Foundation--NSString+NSMutableString

NSString

字符串创建：

　　1.NSString *strr = @"0123456789";

2.NSString *str = [NSString stringWithString:strr];

　　  3.NSString *fstr = [NSString stringWithFormat:@"age = %d",age];

字符串长度；

NSUInteger len = str.length;

字符串获取子字符串：

1.NSString *fromStr = [str substringFromIndex:4];

2.NSString *toStr = [str substringToIndex:4];

3.NSRange range =NSMakeRange(4, 2);

NSString *rangeStr = [str substringWithRange:range];

字符串比较：

　　  1.if([@"abc" isEqualToString:@"abc"])  //返回YES NO

2.NSComparisonResult result =[@"abc" compare:@"bc"];

switch (result) {

case NSOrderedSame:

NSLog(@"same");

break;

case NSOrderedAscending:

NSLog(@"abc<bc");

break;

case NSOrderedDescending:

NSLog(@"abc>bc");

break;

default:

break;

}

字符串查找：

　　    NSString *url = @"http://www.baidu.com";

1.if ([url hasPrefix:@"http"])  //前缀

2.if ([url hasSuffix:@"com"]) //后缀

3.//字符串位置

NSRange rr =[url rangeOfString:@"www"];

if (rr.length) {

NSLog(@"%ld  %ld",rr.location,rr.length);

}else{

NSLog(@"not found");

}

字符串转换：

　　  //字符串转为数字  只把开头的数字转过来

NSString * heightStr = @"166.5";

float height = [heightStr floatValue];

//数字转为字符串

NSString *formatStr = [NSString stringWithFormat:@"height = %f",height];

NSMutableString

预留内存空间：

NSMutableString *mstr = [[NSMutableString alloc]initWithCapacity:0];

NSMutableString *mstr = [NSMutableString stringWithCapacity:0];

追加：

[mstr appendString:@"小王子"];

int num = 1;

[mstr appendFormat:@"%d 小王子", num ];

插入：

[mstr insertString:@"《" atIndex:0];

[mstr insertString:@"》" atIndex:mstr.length];

改：

NSRange rm =[mstr rangeOfString:@"小王子"];

[mstr replaceCharactersInRange:rm withString:@"大王子"];

重置：

[mstr setString:@"大王子"];

删：

NSRange rmm =[mstr rangeOfString:@"大"];

[mstr deleteCharactersInRange:rmm];