//判断是否包含前后缀
NSString *string = @"I love China";
BOOL isHasI = [string hasPrefix:@"I"];
BOOL isHasChina = [string hasSuffix:@"China"];
//替换字符串
NSString *string = @"I love China";
NSString *replaceString = [string stringByReplacingOccurrencesOfString:@"love" withString:@"like"];
NSLog(@"replaceString: %@",replaceString);
//去除字符串首尾的空格和换行符
NSString *string = @" I love China ";
NSString *text = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
NSLog(@"text:%@",text);
