diff short_reads_trim_seq.py @ 0:8c0b907e6e5b draft

Imported from capsule None

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/short_reads_trim_seq.py	Mon May 19 10:59:57 2014 -0400
@@ -0,0 +1,234 @@
+#!/usr/bin/env python
+"""
+trim reads based on the quality scores
+input: read file and quality score file
+output: trimmed read file
+"""
+
+import os, sys, math, tempfile, re
+
+assert sys.version_info[:2] >= ( 2, 4 )
+
+def stop_err( msg ):
+    sys.stderr.write( "%s\n" % msg )
+    sys.exit()
+
+def append_to_outfile( outfile_name, seq_title, segments ):
+    segments = segments.split( ',' )
+    if len( segments ) > 1:
+        outfile = open( outfile_name, 'a' )
+        for i in range( len( segments ) ):
+            outfile.write( "%s_%d\n%s\n" % ( seq_title, i, segments[i] ) )
+        outfile.close()
+    elif segments[0]:
+        outfile = open( outfile_name, 'a' )
+        outfile.write( "%s\n%s\n" % ( seq_title, segments[0] ) )
+        outfile.close()
+
+def trim_seq( seq, score, arg, trim_score, threshold ):
+    seq_method = '454'
+    trim_pos = 0
+    # trim after a certain position
+    if arg.isdigit():
+        keep_homopolymers = False
+        trim_pos = int( arg )    
+        if trim_pos > 0 and trim_pos < len( seq ):
+            seq = seq[0:trim_pos]
+    else:
+        keep_homopolymers = arg=='yes'
+        
+    new_trim_seq = ''
+    max_segment = 0
+
+    for i in range( len( seq ) ):
+        if i >= len( score ):
+            score.append(-1)   
+        if int( score[i] ) >= trim_score:
+            pass_nuc = seq[ i:( i + 1 ) ]
+        else:
+            if keep_homopolymers and ( (i == 0 ) or ( seq[ i:( i + 1 ) ].lower() == seq[ ( i - 1 ):i ].lower() ) ):
+                pass_nuc = seq[ i:( i + 1 ) ]
+            else:
+                pass_nuc = ' '    
+        new_trim_seq = '%s%s' % ( new_trim_seq, pass_nuc )
+        # find the max substrings
+        segments = new_trim_seq.split()
+        max_segment = ''
+        len_max_segment = 0
+        if threshold == 0:
+            for seg in segments:
+                if len_max_segment < len( seg ):
+                    max_segment = '%s,' % seg
+                    len_max_segment = len( seg )
+                elif len_max_segment == len( seg ):
+                    max_segment = '%s%s,' % ( max_segment, seg )
+        else:
+            for seg in segments:
+                if len( seg ) >= threshold:
+                    max_segment = '%s%s,' % ( max_segment, seg )
+    return max_segment[ 0:-1 ]
+
+def __main__():
+    
+    try:
+        threshold_trim = int( sys.argv[1].strip() )
+    except:
+        stop_err( "Minimal quality score must be numeric." )
+    try:
+        threshold_report = int( sys.argv[2].strip() )
+    except:
+        stop_err( "Minimal length of trimmed reads must be numeric." )
+    outfile_seq_name = sys.argv[3].strip()
+    infile_seq_name = sys.argv[4].strip()
+    infile_score_name = sys.argv[5].strip()
+    arg = sys.argv[6].strip()
+
+    seq_infile_name = infile_seq_name
+    score_infile_name = infile_score_name
+    
+
+    # Determine quailty score format: tabular or fasta format within the first 100 lines
+    seq_method = None
+    data_type = None
+    for i, line in enumerate( file( score_infile_name ) ):
+        line = line.rstrip( '\r\n' )
+        if not line or line.startswith( '#' ):
+            continue
+        if data_type == None:
+            if line.startswith( '>' ):
+                data_type = 'fasta'
+                continue
+            elif len( line.split( '\t' ) ) > 0:
+                fields = line.split()
+                for score in fields:
+                    try:
+                        int( score )
+                        data_type = 'tabular'
+                        seq_method = 'solexa'
+                        break
+                    except:
+                        break
+        elif data_type == 'fasta':
+            fields = line.split()
+            for score in fields:
+                try: 
+                    int( score )
+                    seq_method = '454'
+                    break
+                except:
+                    break
+        if i == 100:
+            break
+
+    if data_type is None:
+        stop_err( 'This tool can only use fasta data or tabular data.' ) 
+    if seq_method is None:
+        stop_err( 'Invalid data for fasta format.')
+    
+    if os.path.exists( seq_infile_name ) and os.path.exists( score_infile_name ):
+        seq = None
+        score = None
+        score_found = False
+        
+        score_file = open( score_infile_name, 'r' )
+
+        for i, line in enumerate( open( seq_infile_name ) ):
+            line = line.rstrip( '\r\n' )
+            if not line or line.startswith( '#' ):
+                continue
+            if line.startswith( '>' ):
+                if seq:
+                    scores = []
+                    if data_type == 'fasta':
+                        score = None
+                        score_found = False
+                        score_line = 'start'
+                        while not score_found and score_line:
+                            score_line = score_file.readline().rstrip( '\r\n' )
+                            if not score_line or score_line.startswith( '#' ):
+                                continue
+                            if score_line.startswith( '>' ):
+                                if score:
+                                    scores = score.split()
+                                    score_found = True    
+                                score = None
+                            else:
+                                for val in score_line.split():
+                                    try:
+                                        int( val ) 
+                                    except:
+                                        score_file.close()
+                                        stop_err( "Non-numerical value '%s' in score file." % val )
+                                if not score:
+                                    score = score_line
+                                else:
+                                    score = '%s %s' % ( score, score_line )                                        
+                    elif data_type == 'tabular':
+                        score = score_file.readline().rstrip('\r\n')
+                        loc = score.split( '\t' )
+                        for base in loc:
+                            nuc_error = base.split()
+                            try:
+                                nuc_error[0] = int( nuc_error[0] )
+                                nuc_error[1] = int( nuc_error[1] )
+                                nuc_error[2] = int( nuc_error[2] )
+                                nuc_error[3] = int( nuc_error[3] )
+                                big = max( nuc_error )
+                            except:
+                                score_file.close()
+                                stop_err( "Invalid characters in line %d: '%s'" % ( i, line ) )
+                            scores.append( big )
+                    if scores:
+                        new_trim_seq_segments = trim_seq( seq, scores, arg, threshold_trim, threshold_report )
+                        append_to_outfile( outfile_seq_name, seq_title, new_trim_seq_segments )  
+                                
+                seq_title = line
+                seq = None
+            else:
+                if not seq:
+                    seq = line
+                else:
+                    seq = "%s%s" % ( seq, line )
+        if seq:
+            scores = []
+            if data_type == 'fasta':
+                score = None
+                while score_line:
+                    score_line = score_file.readline().rstrip( '\r\n' )
+                    if not score_line or score_line.startswith( '#' ) or score_line.startswith( '>' ):
+                        continue
+                    for val in score_line.split():
+                        try:
+                            int( val )
+                        except:
+                            score_file.close()
+                            stop_err( "Non-numerical value '%s' in score file." % val )
+                    if not score:
+                        score = score_line
+                    else:
+                        score = "%s %s" % ( score, score_line ) 
+                if score: 
+                    scores = score.split()
+            elif data_type == 'tabular':
+                score = score_file.readline().rstrip('\r\n')
+                loc = score.split( '\t' )
+                for base in loc:
+                    nuc_error = base.split()
+                    try:
+                        nuc_error[0] = int( nuc_error[0] )
+                        nuc_error[1] = int( nuc_error[1] )
+                        nuc_error[2] = int( nuc_error[2] )
+                        nuc_error[3] = int( nuc_error[3] )
+                        big = max( nuc_error )
+                    except:
+                        score_file.close()
+                        stop_err( "Invalid characters in line %d: '%s'" % ( i, line ) )
+                    scores.append( big )
+            if scores:
+                new_trim_seq_segments = trim_seq( seq, scores, arg, threshold_trim, threshold_report )
+                append_to_outfile( outfile_seq_name, seq_title, new_trim_seq_segments )  
+        score_file.close()
+    else:
+        stop_err( "Cannot locate sequence file '%s'or score file '%s'." % ( seq_infile_name, score_infile_name ) )    
+
+if __name__ == "__main__": __main__()