foundation 框架 NSString常用总结(二)

以此作为NSString常用总结（一）的补充

　　　　　NSString* str = [NSString stringWithFormat:@"I love programing! You, come here"];
        //字符串对象的大小写转换
        //转换为大写
        NSString* upStr = [str uppercaseString];
        NSLog(@"str = %@", str);
        NSLog(@"upStr = %@", upStr);
        //转换为小写
        NSString* lowerStr = [str lowercaseString];
        NSLog(@"lowerStr = %@", lowerStr);
        //转换成首字母大写
        NSString* newStr = [str capitalizedString];
        NSLog(@"newStr = %@", newStr);
        
        //字符串提取
        //指定位置到结尾：
        NSString* subStr = [str substringFromIndex:7];
        NSLog(@"subStr = %@", subStr);
        //从指定位置提取指定长度(通过 NSRange)
        subStr = [str substringWithRange: NSMakeRange(7, 7)];
         NSLog(@"subStr = %@", subStr);
        //开头到指定位置
        subStr = [str substringToIndex:6];
         NSLog(@"subStr = %@", subStr);
        
        //字符串切割(componentsSeparatedByString:)方法
        //此方法根据传递的字符串进行分割，并将分割的结果以数组返回
        NSArray* strArr = [str componentsSeparatedByString:@" "];
        for (id str in strArr) {
            NSLog(@"%@", str);
        }
        //拼接数组中得字符串(按指定字符串)
        NSString* myStr = [strArr componentsJoinedByString:@"__"];
        NSLog(@"mystr = %@", myStr);
        //根据传递进来的NSCharacterSet集合进行分割(示例中包含逗号“,”和空格“ ”)
        strArr = [str componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@", "]];
        for (id str in strArr) {
            NSLog(@"%@", str);
        }