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  • dontkme
    Junior Member
    • Apr 2013
    • 2

    Is there an easy way to filter SAM/BAM files with NM>0

    Hi, everyone

    BAM files contain the informations like
    "AS:i:-8 XM:i:0 XO:i:0 XG:i:0 MD:Z:100 NM:i:0 XS:A:+ NH:i:1".
    NM means not matched bp numbers.

    Now I wanted to pick the reads that are totally mapped to the ref sequence.

    I have tried to use Picard SamToFastq and tophat/bowtie2 -N 0 to get the final BAM, but samtools view -f 8 cannot correctly pick the single mapped reads, so SamToFastq didin't work well.

    So is there an easy way to filter SAM/BAM files with NM>0 .

    Thanks.
  • lindenb
    Senior Member
    • Apr 2010
    • 143

    #2
    Using my program sam.js https://github.com/lindenb/jvarkit/wiki/SamJS

    Code:
     java -jar  dist/samjs.jar  -e 'parseInt(record.getAttribute("NM"))===0'  your.bam

    Comment

    • Chipper
      Senior Member
      • Mar 2008
      • 323

      #3
      This should give you the NM:0 alignments in sam format:

      samtools view file.bam | awk '$0 ~"NM:i:0"' > perfect-match.sam

      Comment

      • dontkme
        Junior Member
        • Apr 2013
        • 2

        #4
        Originally posted by Chipper View Post
        This should give you the NM:0 alignments in sam format:

        samtools view file.bam | awk '$0 ~"NM:i:0"' > perfect-match.sam
        Thanks it worked well.

        I added the header and IGV can use the bam.

        Comment

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