[string uppercaseString];
（3）首字母大写
复制代码
NSString *string = @"ligang";
NSLog(@"string: %@",[string capitalizedString]);
打印：
2015-07-16 23:06:11.652 iOSStrongDemo[10279:3062010] string: Ligang
5.截取字符串
（1）substringToIndex截取字符串
复制代码NSString *string = @"This is a operation string!";
NSString *subToString = [string substringToIndex:6];
（2）截取的subToString为This i
substringFromIndex截取字符串
复制代码NSString *subFromString = [string substringFromIndex:6];
（3）截取的subFromString为s a operation string!
substringWithRange截取字符串
复制代码NSString *rangeString = [string substringWithRange:NSMakeRange(6, 3)];
截取的rangeString为s a!
6.判断字符串是否包含另一个字符串
（1）rangeOfString判断
复制代码NSString *string1 = @"This is a iOSDevTip";
NSString *string2 = @"iOSDevTip";
NSRange range = [string1 rangeOfString:string2];
NSInteger location = range.location;
NSInteger leight = range.length;
NSString *logString = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%ld,Leight:%ld",location,leight]];
NSLog(@"logString:%@",logString);
打印出来：
iOSStrongDemo[8837:2221170] logString:Location:10,Leight:9
（2）判断是否包含前后缀
复制代码NSString *string = @"I love China";
BOOL isHasI = [string hasPrefix:@"I"];
BOOL isHasChina = [string hasSuffix:@"China"];
7.分割字符串
复制代码NSString *string = @"This is a iOSDevTip";
NSArray *array = [string componentsSeparatedByString:@"a"];
NSString *string1 = [array objectAtIndex:0];
NSString *string2 = [array objectAtIndex:1];
NSLog(@"string1:%@ string2:%@",string1,string2);
