Question

所以我一直在尝试使用一个txt文件，例如 -

这样的输入

abcddhdj
efghdd
ijkl

得到这个 -

j
d
hd
dd
dhl
cgk
bfj
aei

我试图使用2d char数组执行此操作，它给出了nullexception和arrayoutofbound错误并且大部分都没有工作，然后尝试了字符串数组，字符串的arraylist，最后我一直在尝试使用字符串的arraylsit

这是我使用string [] -

进行大量搜索后最接近我的解决方案

public static void main(String[] args) throws IOException
{
    BufferedReader br = new BufferedReader(new FileReader("C:\\test.txt"));         // PUT YOUR FILE LOCATION HERE
    int k=0,i,j=0,x;
    String line[] = new String[10] ;     //SET THE APPROXIMATE NUMBER OF ROWS
    while((line[k] = br.readLine()) !=null)
        {System.out.println(line[k]);      //print to check input - verified
         k++;


        }
    for(x=0;x<k;x++)
    {if(j<line[x].length())
       {j=line[x].length()-1;}    //this part not working in above loop
    }
    System.out.println(j);    // verified but not working inside previous loop for some reason
    System.out.println(k);


    for(x=j-1;x>=0;x++)         //without this loop,its perfect, but with it gives  indexoutofbound error , doesnt run at x=j
    {  for(i=0;i<k;i++)
       { System.out.print(line[i].charAt(x));
       } 
       System.out.println();
    }

}

这是一个输出

run:
abcd
efgh
ijkl
4     //should have come as 3 since i did length-1
3
chl     //notice the d missing , every char of first row shifted,just why
bgk    //in outofbound error , it only prints d at the end, need explanation 
afj
ei
BUILD SUCCESSFUL (total time: 0 seconds)

如果我在abcd之后添加一个空格，它会给出indexoutofbound并且在k之后没有输出最后，我使用另一种方法，增加空格，使所有长度相等然而输出仍然是错误的，加上这种思维方式有问题，应该有更好的方法

所以我尝试了arraylist，这再次给了我更多的问题

尝试以任何可理解的方法解决这个问题。

Answer 1

这应该是诀窍：

这里的关键是我用空字符填充所有行数组，以便每个字符数组与最长行的长度相同。

public static void main(String[] args)
{
    try (BufferedReader br = new BufferedReader(new FileReader("C:\\test.txt")))
    {
        String line;
        List<List<Character>> lines = new ArrayList<>();

        int longestLine = 0;
        while((line = br.readLine()) !=null)
        {
            line = line.trim();

            if (line.length() > 0)
            {
                List<Character> currList = new ArrayList<>();
                for (char c : line.toCharArray())
                {
                    currList.add(c);
                }

                if (currList.size() > longestLine)
                {
                    longestLine = currList.size();
                }

                lines.add(currList);
            }
        }

        // pad all lists to be the same as the longest
        for (List<Character> currList : lines)
        {
            while (currList.size() < longestLine)
            {
                currList.add(Character.MIN_VALUE);
            }
        }

        // go through each list backwards
        for (int i = longestLine - 1; i >= 0; i-- )
        {
            for (List<Character> currList : lines)
            {
                System.out.print(currList.get(i));
            }
            System.out.println();
        }
    }
    catch (Throwable t)
    {
        t.printStackTrace();
    }
}

示例输入：

abcd
efgh
ijkl
g

示例输出：

dhl
cgk
bfj
aeig

Answer 2

假设输入被读入arraylist

ArrayList<String> inputList = new ArrayList<String>();
inputList.add("abcddhdj");
inputList.add("efghdd");
inputList.add("ijkl");

int maxSize = 0;
for (String input : inputList) {
    if (input.length() > maxSize) {
        maxSize = input.length();
    }
}
String outputList[] = new String[maxSize];
for (int i = 0; i < maxSize; i++) {
    String output = "";
    for (String input : inputList) {
      if(i<input.length())
          output=output+input.charAt(i);
    }
    outputList[maxSize-(i+1)]=output;
}

Answer 3

将所有内容存储到直接2d阵列并在打印循环中进行转置

    final char[][] matrix = Files.lines(Paths.get(fileName)).map(String::toCharArray).toArray(char[][]::new);
    final int width = Arrays.stream(matrix).mapToInt(a -> a.length).max().getAsInt();

    for (int i = 0; i < width; ++i ) {
        final int idx = width-i-1;
        String s = Arrays.stream(matrix).map(a -> a.length > idx ? String.valueOf(a[idx]) : " ").collect(Collectors.joining());
        System.out.println(s);
    }

试图打印转置字符串[]

3 个答案: