--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/filtering.py	Fri Jul 15 09:41:23 2011 -0400
@@ -0,0 +1,128 @@
+#!/usr/bin/env python
+# This tool takes a tab-delimited text file as input and creates filters on columns based on certain properties.
+# The tool will skip over invalid lines within the file, informing the user about the number of lines skipped.
+
+from __future__ import division
+import sys, re, os.path
+from galaxy import eggs
+
+# Older py compatibility
+try:
+    set()
+except:
+    from sets import Set as set
+
+assert sys.version_info[:2] >= ( 2, 4 )
+
+def get_operands( filter_condition ):
+    # Note that the order of all_operators is important
+    items_to_strip = ['+', '-', '**', '*', '//', '/', '%', '<<', '>>', '&', '|', '^', '~', '<=', '<', '>=', '>', '==', '!=', '<>', ' and ', ' or ', ' not ', ' is ', ' is not ', ' in ', ' not in ']
+    for item in items_to_strip:
+        if filter_condition.find( item ) >= 0:
+            filter_condition = filter_condition.replace( item, ' ' )
+    operands = set( filter_condition.split( ' ' ) )
+    return operands
+
+def stop_err( msg ):
+    sys.stderr.write( msg )
+    sys.exit()
+
+in_fname = sys.argv[1]
+out_fname = sys.argv[2]
+cond_text = sys.argv[3]
+try:
+    in_columns = int( sys.argv[4] )
+    assert sys.argv[5]  #check to see that the column types varaible isn't null
+    in_column_types = sys.argv[5].split( ',' )
+except:
+    stop_err( "Data does not appear to be tabular.  This tool can only be used with tab-delimited data." )
+
+# Unescape if input has been escaped
+mapped_str = {
+    '__lt__': '<',
+    '__le__': '<=',
+    '__eq__': '==',
+    '__ne__': '!=',
+    '__gt__': '>',
+    '__ge__': '>=',
+    '__sq__': '\'',
+    '__dq__': '"',
+}
+for key, value in mapped_str.items():
+    cond_text = cond_text.replace( key, value )
+    
+# Attempt to determine if the condition includes executable stuff and, if so, exit
+secured = dir()
+operands = get_operands(cond_text)
+for operand in operands:
+    try:
+        check = int( operand )
+    except:
+        if operand in secured:
+            stop_err( "Illegal value '%s' in condition '%s'" % ( operand, cond_text ) )
+
+# Prepare the column variable names and wrappers for column data types
+cols, type_casts = [], []
+for col in range( 1, in_columns + 1 ):
+    col_name = "c%d" % col
+    cols.append( col_name )
+    col_type = in_column_types[ col - 1 ]
+    type_cast = "%s(%s)" % ( col_type, col_name )
+    type_casts.append( type_cast )
+ 
+col_str = ', '.join( cols )    # 'c1, c2, c3, c4'
+type_cast_str = ', '.join( type_casts )  # 'str(c1), int(c2), int(c3), str(c4)'
+assign = "%s = line.split( '\\t' )" % col_str
+wrap = "%s = %s" % ( col_str, type_cast_str )
+skipped_lines = 0
+first_invalid_line = 0
+invalid_line = None
+lines_kept = 0
+total_lines = 0
+out = open( out_fname, 'wt' )
+    
+# Read and filter input file, skipping invalid lines
+code = '''
+for i, line in enumerate( file( in_fname ) ):
+    total_lines += 1
+    line = line.rstrip( '\\r\\n' )
+    if not line or line.startswith( '#' ):
+        skipped_lines += 1
+        if not invalid_line:
+            first_invalid_line = i + 1
+            invalid_line = line
+        continue
+    try:
+        %s
+        %s
+        if %s:
+            lines_kept += 1
+            print >> out, line
+    except:
+        skipped_lines += 1
+        if not invalid_line:
+            first_invalid_line = i + 1
+            invalid_line = line
+''' % ( assign, wrap, cond_text )
+
+valid_filter = True
+try:
+    exec code
+except Exception, e:
+    out.close()
+    if str( e ).startswith( 'invalid syntax' ):
+        valid_filter = False
+        stop_err( 'Filter condition "%s" likely invalid. See tool tips, syntax and examples.' % cond_text )
+    else:
+        stop_err( str( e ) )
+
+if valid_filter:
+    out.close()
+    valid_lines = total_lines - skipped_lines
+    print 'Filtering with %s, ' % cond_text
+    if valid_lines > 0:
+        print 'kept %4.2f%% of %d lines.' % ( 100.0*lines_kept/valid_lines, total_lines )
+    else:
+        print 'Possible invalid filter condition "%s" or non-existent column referenced. See tool tips, syntax and examples.' % cond_text
+    if skipped_lines > 0:
+        print 'Skipped %d invalid lines starting at line #%d: "%s"' % ( skipped_lines, first_invalid_line, invalid_line )