bash - 如何使用同一列中前一个单元格的数据填充 CSV 中的空单元格？

Question

我有一个很大的制表符分隔的 CSV 文件。但是，它缺少一些数据:

1      cat    The cat ate the fish.
       dog    The dog played in the yard.
       fish   The fish went to the river.
2      eagle  The eagle flew in the sky.
              The eagle stopped in the mountains.
       bear   The bear ate the honey.

我需要用前一行中出现的任何数据填充所有空单元格。输出将如下所示:

1      cat    The cat ate the fish.
1      dog    The dog played in the yard.
1      fish   The fish went to the river.
2      eagle  The eagle flew in the sky.
2      eagle  The eagle stopped in the mountains.
2      bear   The bear ate the honey.

• 最好，该方法一次仅编辑一个指定的列，并且必须针对指定的不同列运行多次，才能完全填充整个 CSV。

有没有办法用具有数据的同一列中的前一个单元格的内容填充 CSV 中的空单元格？

Answer 1

awk 解决整个文件:

awk -F\\t '
    {
      for (i=1;i<=NF;++i) if ($i != "") a[i] = $i;
      if (na < NF) na = NF;
      for (i=1;i<na;++i) printf "%s\t", a[i]
      printf "%s\n", a[na];
    }
    ' file.tsv

仅执行指定列:

awk -F\\t -v COL=2 '
    $COL=="" {$COL = saved}
    {saved = $COL; print}
    ' file.tsv