iOS learning string (NSString) taken match, the partition

Interception

NSString *str1 = @"this is zero";

1.从第三个字符开始，截取长度为2的字符串.........注:空格算作一个字符
NSString *str2 = [str1 substringWithRange:NSMakeRange(5,2)];//str2 = "is" 2.截取从0位到第n为（第n位不算在内） NSString *str3 = [str1 substringToIndex:4];//str3 = "this" 3.从第n为开始直到最后（包含第n位） NSString *str4 = [str1 substringFromIndex:8];//str4 = "zero" 4.截取字符串的后4位 NSString *str5 = [str1 substringFromIndex:a.length-5];//str5 = "zero"........注：字符串的位数是在0位开始，所以截取后4位，应该是减5 

match

NSString *string =@"sd是sfsfsAdfsdf";
NSRange range = [string rangeOfString:@"Ad"];//匹配得到的下标 NSLog(@"rang:%@",NSStringFromRange(range)); rang:{8, 2} string = [string substringWithRange:range];//截取范围内的字符串 NSLog(@"截取的值为：%@",string);截取的值为：Ad 

Separated

NSString *string =@"sdfsfsfsAdfsdf";
NSArray *array = [string componentsSeparatedByString:@"A"]; //从字符A中分隔成2个元素的数组 NSLog(@"array:%@",array); //结果是adfsfsfs和dfsdf 

And transforming the array of strings (with a separator)

将string字符串转换为array数组
 NSArray  *array = [str componentsSeparatedByString:@","];--分隔符

将array数组转换为string字符串 NSString *str = [array componentsJoinedByString:@","];--分隔符