+(NSString *) stringDeleteString:(NSString *)str

{

    NSMutableString *str1 = [NSMutableString stringWithString:str];

    for (int i = 0; i < str1.length; i++) {

        unichar c = [str1 characterAtIndex:i];

        NSRange range = NSMakeRange(i, 1);

        if (|| c == '"' || c == '.' || c == ',' || c == '(' || c == ')') { //此处可以是任何字符

            [str1 deleteCharactersInRange:range];

            --i;

        }

    }

    NSString *newstr = [NSString stringWithString:str1];

    return newstr;

}

可以删除nsstring中的数字、符号，或者修改其中的字符