在给定 grep 结果的情况下，在第三列中查找具有最低值的行

Question

我有一个由这样的行组成的文件（包括其他数字）。这是输出的一部分

$ grep 1848 filename.csv

.csv假设 1848 位于第一列或第二列，如何找到文件中第三列最低的前 5 行？

1848,2598,11.310694021273559
1848,2599,10.947275955606203
1848,2600,10.635270124233982
1848,2601,11.916564552040725
1848,2602,12.119810736845844
1848,2603,12.406661156256154
1848,2604,10.636275056472996
1848,2605,12.549890992708612
1848,2606,9.783802450936204
1848,2607,11.253697489670264
1848,2608,12.16385432290674
1848,2609,10.30355814063016
1848,2610,12.102525596913923
1848,2611,11.636595992818505
1848,2612,10.741178028606866
1848,2613,11.352414275107423
1848,2614,12.204860161717253
1848,2615,12.959915468475387
1848,2616,11.320652192610872

不幸的是，1848 有时也会出现在第三列中，我需要忽略它：

6687,8963,9.241848677632822
6687,9111,10.537325656184889
6687,9506,11.315629894841848

Answer 1

使用 GNU 排序：

grep -E '(^1848|^[0-9]{4},1848)' file | sort -t, -k3n | head -n 5

（如果第一列可能少于或多于 4 位数字，请替换{4}为+）

输出：

1848,2606,9.783802450936204
1848,2609,10.30355814063016
1848,2600,10.635270124233982
1848,2604,10.636275056472996
1848,2612,10.741178028606866

Answer 2

只需awk：

awk -F, 'BEGIN{PROCINFO["sorted_in"]="@ind_num_asc"} \
          $1==1848||$2==1848 {a[$3]=$0} END {for(i in a) print a[i]}' file.csv

• BEGIN{PROCINFO["sorted_in"]="@ind_num_asc"} 设置将根据索引，根据数字，以升序方式创建的任何数组的顺序

• $1==1848||$2==1848 {a[$3]=$0}检查第一个或第二个字段是否为 1848，如果是，则将第三个字段 ( $3) 作为数组a索引，其值为整个记录 ( $0)

• 在 中END {for(i in a) print a[i]}，我们简单地迭代键并打印值

要仅获取 5 条记录，请head -5在末尾添加：

awk ... | head -5

为了完整起见，您显然可以通过break在END循环中加入一个微小的逻辑来只获得前 5 条记录，不需要tail：

awk -F, 'BEGIN{PROCINFO["sorted_in"]="@ind_num_asc"} \
          $1==1848||$2==1848 {a[$3]=$0} END {j=0; for(i in a) \
           {print a[i]; j++; if(j==5) break}}' file.csv

例子：

% cat file.txt
1848,2598,11.310694021273559
1848,2599,10.947275955606203
1848,2600,10.635270124233982
1848,2601,11.916564552040725
1848,2602,12.119810736845844
1848,2603,12.406661156256154
1848,2604,10.636275056472996
1848,2605,12.549890992708612
1848,2606,9.783802450936204
1848,2607,11.253697489670264
1848,2608,12.16385432290674
1848,2609,10.30355814063016
1848,2610,12.102525596913923
1848,2611,11.636595992818505
1848,2612,10.741178028606866
1848,2613,11.352414275107423
1848,2614,12.204860161717253
1848,2615,12.959915468475387
1848,2616,11.320652192610872

% awk -F, 'BEGIN{PROCINFO["sorted_in"]="@ind_num_asc"} $1==1848||$2==1848 {a[$3]=$0} END {for(i in a) print a[i]}' file.txt
1848,2606,9.783802450936204
1848,2609,10.30355814063016
1848,2600,10.635270124233982
1848,2604,10.636275056472996
1848,2612,10.741178028606866
1848,2599,10.947275955606203
1848,2607,11.253697489670264
1848,2598,11.310694021273559
1848,2616,11.320652192610872
1848,2613,11.352414275107423
1848,2611,11.636595992818505
1848,2601,11.916564552040725
1848,2610,12.102525596913923
1848,2602,12.119810736845844
1848,2608,12.16385432290674
1848,2614,12.204860161717253
1848,2603,12.406661156256154
1848,2605,12.549890992708612
1848,2615,12.959915468475387

% awk -F, 'BEGIN{PROCINFO["sorted_in"]="@ind_num_asc"} $1==1848||$2==1848 {a[$3]=$0} END {j=0; for(i in a) {print a[i]; j++; if(j==5) break}}' file.txt 
1848,2606,9.783802450936204
1848,2609,10.30355814063016
1848,2600,10.635270124233982
1848,2604,10.636275056472996
1848,2612,10.741178028606866