awk next 和模式匹配

Question

如果我们有以下csv文件，我们只想得到"DELTA Energy Terns"部分的$9，不包括"Frame"

开头的行

Ligand Energy Terms
Frame #,VDWAALS,EEL,EGB,ESURF,ESCF,G gas,G solv,TOTAL
0,0.0,0.0,-37.2465,2.70257904,98.8916,0.0,-34.54392096,64.34767904
1,0.0,0.0,-33.1958,2.71419624,80.6403,0.0,-30.48160376,50.15869624

DELTA Energy Terms
Frame #,VDWAALS,EEL,EGB,ESURF,ESCF,DELTA G gas,DELTA G solv,DELTA TOTAL
0,-43.3713,0.0,44.4036,-5.24443392,-27.4605,-43.3713,39.15916608,-31.67263392
1,-43.7597,0.0,37.343,-5.1764544,-23.3471,-43.7597,32.1665456,-34.9402544
2,-42.5618,0.0,44.0748,-5.2738956,-26.6719,-42.5618,38.8009044,-30.4327956
3,-43.1034,0.0,41.3681,-5.25029544,-27.1501,-43.1034,36.11780456,-34.13569544

期望的输出：

-31.6726
-34.9402
-30.4327
-34.1356

以下尝试将打印出所有的$9，包括"Ligand Energy Terms"部分的$9。

awk -F, ' ~ /DELTA Energy Terms/ {next}  ~ /Frame/ {next} {printf("%24.4f\n",)}'

awk -F, ' ~ /DELTA Energy Terms/ {next}  {printf("%24.4f\n",)}'

有哪位大神能开导一下吗？

Answer 1

您可以尝试以下 awk 命令。

$ awk -v RS="\n\n" -v FS="\n" '/^DELTA Energy Terms/{for(i=3;i<=NF;i++){split($i, a, /,/);print a[9]}}' RS=  file
-31.67263392
-34.9402544
-30.4327956
-34.13569544

RS="\n\n"，所以记录分隔符设置了一个空行。
FS="\n"，换行符设置为字段分隔符。
/^DELTA Energy Terms/ 如果记录以 ^DELTA Energy Terms 开头，则对该特定记录执行以下操作。
{for(i=3;i<=NF;i++){split($i, a, /,/);print a[9]}}遍历除1和2以外的所有字段，然后按照逗号拆分每个字段，然后将拆分的项目存储到名为a.
print a[9] 打印关联数组 a.

Answer 2

下面应该可以解决问题

awk -F, '/^DELTA/ {capture=1} /Energy Terms$/ {next} /^Frame/ {next} (capture) {print }'

我使用 capture 标志来控制是否应捕获单个记录。默认情况下 capture 为零。当解析 DELTA Energy Terms 行时，我开始捕获。我跳过任何以 Energy Terms 结尾或以 Frame 开头的行。否则，如果我们是"capturing"，那我把第九个元素拿出来

如果您经常使用此脚本，我建议您使用类似以下的脚本：

#!/usr/bin/awk -f
BEGIN {
    FS = ","
}
/^DELTA Energy Terms/ {
    capture = 1;
    next
}
/Energy Terms$/ {
    capture = 0;
    next
}
/^Frame/ { next }
(capture) { print  }

将脚本保存为 extract-delta 并使其可执行，然后您就可以像使用任何其他 shell 命令一样使用它了：

$ cat input-file | tr -d '5' | ./extract-delta
-31.67263392
-34.9402544
-30.4327956
-34.13569544

Answer 3

您也可以通过 bash 完成此操作，方法如下：

tail -n +$((2 + $(grep -n "DELTA Energy Terms" input.txt | cut -d":" -f1) )) input.txt | cut -d"," -f9

tail -n +$((2 + $(grep -n "DELTA Energy Terms" input.txt 部分将从包含 DELTA Energy Terms 的行开始打印输入文件的行加 2，然后 cut 将给出你是你正在寻找的第 9 个字段。

Answer 4

所有这些解决方案都有效，因此解决了眼前的问题，但 none 回答了隐含的问题。

查看有问题的命令，为什么它不起作用？

' ~ /DELTA Energy Terms/ {next}  ~ /Frame/ {next} {printf("%24.4f\n",)}

让我们分解一下。

# Skip every line where the first field matches. 
 ~ /DELTA Energy Terms/ {next} 
  # No line matches this criteria, so this has no effect. 
  # Explanation: The field separator isn't set, so defaults to breaking fields on white space. 
  # If you print out the first field, you will see "DELTA" on this line, not "DELTA Energy Terms".

# Skip every line where the first field matches "Frame". 
 ~ /Frame/ {next} 
  # This matches and gets skipped.

# Print every line that didn't get skipped.
{printf("%24.4f\n",)}
  # The two "Energy Terms" title lines don't have any entries in field 9, 
  # so it prints blanks for those lines.

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