AWK关联数组，映射 [英] AWK associative array, mapping

问题描述

假设我有两个文件:

文件1-map.txt

file1 - map.txt

1, 178246
2, 289789
3, 384275
4, 869282

file2-Relation.txt

file2 - relation.txt

178246, 289789
384275, 178246
384275, 869282

预期结果是:

1, 2
3, 1
3, 4

但是我使用以下代码得到的结果是:

But the results I got using the following code were:

awk 'FNR==NR{map[$2]=$1} {$1=map[$1];$2=map[$2];print $0}' map.txt relation.txt

  2,
  1,
  4,

当我像这样交换map.txt中的列时，它很困惑:

It was confused when I swapped the columns in map.txt like this:

178246, 1
289789, 2
384275, 3
869282, 4

relation.txt不变

relation.txt doesn't change

结果变为:

awk 'FNR==NR{map[$1]=$2} {$1=map[$1];$2=map[$2];print $0}' map.txt relation.txt

1,
3,
3,

在{$ 1 = map [$ 1]; $ 2 = map [$ 2]; print $ 0}附近似乎出了什么问题

It seems that something wrong near {$1=map[$1];$2=map[$2];print $0}

推荐答案

删除第2列中两个文件中的前导空格.

Remove the leading space in both files in column 2.

帮自己一个忙，转到FS的逗号以外的内容. Tab字符很不错，因为大多数输入屏幕都使用Tab移至下一个字段，因此它不应包含在您的数据中. | char很不错，因为它很直观，而且不太可能出现在您的输入中.

And do yourself a favor and switch to something besides commas for FS. The Tab char is good because most input screens use tab to move to the next field, so it shouldn't be in your data. The | char is nice because it is visual and very unlikely to be in your input.

您可以构建一个陷阱"以查找没有正确数量的字段的记录，如下所示:

You could build a 'trap' to find records without the right number of fields like this:

awk -F"|" -v expectFldCnt=2 '{
   if (NF==expectFldCnt) { print ":everything OK" ; }
    else { print "ERR: " NF "!=" expectFldCnt  ":" $0 > "errorFile" }
    }' \
  map.txt relation.txt

IHTH

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