拼接：
NSArray *pathArray = [NSArray arrayWithObjects:@"here", @"be", @"dragons", nil];
NSLog(@"%@",[pathArray componentsJoinedByString:@" "]);
分割：
NSString* str = @"here be dragons";
[str componentsSeparatedByString:@" "];
for(NSString* s in str) NSLog(s);
去空格:
NSString
*number_temp = [number stringByReplacingOccurrencesOfString:@" " withString:@""];
转UTF-8:
NSString *bb = [s stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
