如何使用awk在match()函数中使用变量来定义范围"r(n，)" [英] How to define the range 'r(n,)' using a variable in match() function with awk

问题描述

我正在处理文本文件，每个文件有数千条记录.每个记录由两行组成:以>"开头的标头，然后是带有长字符串"-AGTCNR"的行. 这是一个简单文件的样子:

I am processing text files with thousands of records per file. Each record is made up of two lines: a header that starts with ">" and followed by a line with a long string of characters "-AGTCNR". Here is how a simple file looks like:

>ACML500-12|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_-2
----TAAGATTTTGACTTCTTCCCCCATCATCAAGAAGAATTGT-------
>ACRJP458-10|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_N
-----------TCCCTTTAATACTAGGAGCCCCTGACATAGCCTTTCCTAAATAAT-----
>ASILO303-17|Dip|gs-Par|sp-Par vid|subsp-NA|co
-----TAAGATTCTGATTACTCCCCCCCTCTCTAACTCTTCTTCTTCTATAGTAGATG
>ASILO326-17|Dip|gs-Goe|sp-Goe par|subsp-NA|c
TAAGATTTTGATTATTACCCCCTTCATTAACCAGGAACAGGATGA------
>CLT100-09|Lep|gs-Col|sp-Col elg|subsp-NA|co-Buru
AACATTATATTTGGAATTT-------GATCAGGAATAGTCGGAACTTCTCTGAA------
>PMANL2431-12|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_
----ATGCCTATTATAATTGGAGGATTTGGAAAACCTTTAATATT----CCGAAT
>STBOD057-09|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_N
ATCTAATATTGCACATAGAGGAACCTCNGTATTTTTTCTCTCCATCT------TTAG
>TBBUT582-11|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_N
-----CCCCCTCATTAACATTACTAAGTTGAAAATGGAGCAGGAACAGGATGA
>TBBUT583-11|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_N
TAAGATTTTGACTCATTAA----------------AATGGAGCAGGAACAGGATGA
>AFBTB001-09|Col|gs-NA|sp-NA|subsp-NA|co-Ethi|site-NA|lat_N
TAAGCTCCATCC-------------TAGAAAGAGGGG---------GGGTGA
>PMANL2431-12|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_
----ATGCCTATTAGGAAATTGATTAGTACCTTTAATATT----CCGAAT---
>AFBTB003-09|Col|gs-NA|sp-NA|subsp-NA|co-Ethi|site-NA|lat_N
TAAGATTTTGACTTCTGC------CATGAGAAAGA-------------AGGGTGA
>AFBTB002-09|Cole|gs-NA|sp-NA|subsp-NA|co-Ethi|site-NA|lat_N
-------TCTTCTGCTCAT-------GGGGCAGGAACAGGG----------TGA
>ACRJP458-10|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_N
-----------TCCCTTTAATACTAGGAGCCCCTTTCCT----TAAATAAT-----

现在，我尝试搜索每条记录的第二个字段(行)，并且仅提取在$start_gaps开头和结尾处最多具有最大-"个字符(称为空格)的特定记录的记录.行(字段$ 2)的$end_gaps.

Now I am trying to search through the second field (line) of each record and only extract records which have up to a certain maximum number of "-" characters (referred to as gaps) at the beginning $start_gaps and end, $end_gaps, of line(field $2).

我尝试了一些代码，以下代码很有效:

I have tried a few codes and the following came works well:

read -p "Please enter the muximum number of gaps allowed at start position: " start_gaps &&
read -p "Please enter the maximum number of gaps allowed at the end position: " end_gaps &&
awk -v start_g=$start_gaps -v end_g=$end_gaps 'BEGIN{
RS="\n>"; FS="\n"; ORS="\n"; OFS="\n"; }; (x=start_g+1)(y=end_g+1) { 
if ( match($2, "^-{5,}") && match($2, "-{6,}$") ) {
next} else {print x y ">"$0}}' infile > outfile

但是每次我进行正则表达式模式匹配时，我都需要继续使用变量号而无需显式编辑脚本.因此，我尝试了以下操作，但是正则表达式不接受变量.最好的解决方法是什么?

But I need to keep using variable numbers without explicitly editing the script every time i am conducting the regex pattern matching. So i tried the following but the regex do not accept variables. What is the best work around to this?

read -p "Please enter the muximum number of gaps allowed at start position: " start_gaps &&
read -p "Please enter the maximum number of gaps allowed at the end position: " end_gaps &&
awk -v start_g=$start_gaps -v end_g=$end_gaps 'BEGIN{
RS="\n>"; FS="\n"; ORS="\n"; OFS="\n"; }; (x=start_g+1)(y=end_g+1) {
if ( match($2, "^-{x,}") && match($2, "-{y,}$") ) {
next} else {print x y ">"$0}}' infile > outfile

预期结果:

>ASILO303-17|Dip|gs-Par|sp-Par vid|subsp-NA|co  
-----TAAGATTCTGATTACTCCCCCCCTCTCTAACTCTTCTTCTTCTATAGTAGATG
>ASILO326-17|Dip|gs-Goe|sp-Goe par|subsp-NA|c
TAAGATTTTGATTATTACCCCCTTCATTAACCAGGAACAGGATGA------
>CLT100-09|Lep|gs-Col|sp-Col elg|subsp-NA|co-Buru
AACATTATATTTGGAATTT-------GATCAGGAATAGTCGGAACTTCTCTGAA------
>PMANL2431-12|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_
----ATGCCTATTATAATTGGAGGATTTGGAAAACCTTTAATATT----CCGAAT
>STBOD057-09|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_N
ATCTAATATTGCACATAGAGGAACCTCNGTATTTTTTCTCTCCATCT------TTAG
>TBBUT582-11|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_N
-----CCCCCTCATTAACATTACTAAGTTGAAAATGGAGCAGGAACAGGATGA
>TBBUT583-11|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_N
TAAGATTTTGACTCATTAA----------------AATGGAGCAGGAACAGGATGA
>AFBTB001-09|Col|gs-NA|sp-NA|subsp-NA|co-Ethi|site-NA|lat_N
TAAGCTCCATCC-------------TAGAAAGAGGGG---------GGGTGA
>PMANL2431-12|Lep|gs-NA|sp-NA|subsp-NA|co-Buru|site-NA|lat_
----ATGCCTATTAGGAAATTGATTAGTACCTTTAATATT----CCGAAT---
>AFBTB003-09|Col|gs-NA|sp-NA|subsp-NA|co-Ethi|site-NA|lat_N
TAAGATTTTGACTTCTGC------CATGAGAAAGA-------------AGGGTGA

推荐答案

match将变量RLENGTH设置为匹配的子字符串的长度，并加以利用.另外，您不需要为此使用多字符RS.

match sets variable RLENGTH to the matched substring's length, make use of it. Also, you don't need a multi-char RS for this.

awk -v start_g="$start_gaps" -v end_g="$end_gaps" '
/^>/ { hdr=$0; next }
match($0,/^-*/) && RLENGTH<=start_g && match($0,/-*$/) && RLENGTH<=end_g { print hdr; print }
' file

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