Daniel@0: # Part of DML (Digital Music Laboratory)
Daniel@0: # Copyright 2014-2015 Samer Abdallah, University College London
Daniel@0:  
Daniel@0: # This program is free software; you can redistribute it and/or
Daniel@0: # modify it under the terms of the GNU General Public License
Daniel@0: # as published by the Free Software Foundation; either version 2
Daniel@0: # of the License, or (at your option) any later version.
Daniel@0: # 
Daniel@0: # This program is distributed in the hope that it will be useful,
Daniel@0: # but WITHOUT ANY WARRANTY; without even the implied warranty of
Daniel@0: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Daniel@0: # GNU General Public License for more details.
Daniel@0: # 
Daniel@0: # You should have received a copy of the GNU General Public
Daniel@0: # License along with this library; if not, write to the Free Software
Daniel@0: # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
Daniel@0: 
Daniel@0: # -*- coding: utf-8 -*-
Daniel@0: __author__="samer"
Daniel@0: 
Daniel@0: import csv
Daniel@0: from warnings import warn
Daniel@0: 
Daniel@0: import sys
Daniel@0: import time
Daniel@0: def print_status(msg): sys.stderr.write(msg+'\n')
Daniel@0: 
Daniel@0: # call function for each row of a CSV that has ncols columns.
Daniel@0: # A warning is printed if any rows have the wrong number of columns.
Daniel@0: #
Daniel@0: # csv_for_each : string, integer, (list(string) -> void) -> void
Daniel@0: def csv_for_each(filename,ncols,f):
Daniel@0:     badcount=0
Daniel@0:     with open(filename,'rb') as csvfile:
Daniel@0:         contents=csv.reader(csvfile, delimiter=',',quotechar='"')
Daniel@0:         for row in contents:
Daniel@0:             if len(row)==ncols: f(row)
Daniel@0:             else: badcount += 1
Daniel@0:     # if badcount>0: warn("Ignoring %d malformed rows in CSV file %s" % (badcount,filename))
Daniel@0: 
Daniel@0: # map f over list of rows from CSV to list of values
Daniel@0: #
Daniel@0: # csv_map_rows : string, integer, (list(string) -> A) -> list(A)
Daniel@0: def csv_map_rows(filename,ncols,f):
Daniel@0:     good=[]
Daniel@0:     def append_row(row): good.append(f(row))
Daniel@0:     csv_for_each(filename,ncols,append_row)
Daniel@0:     return good
Daniel@0: 
Daniel@0: def id(x): return x
Daniel@0: 
Daniel@0: 
Daniel@0: # returns selected columns of CSV, one list per column
Daniel@0: #
Daniel@0: # csv_columns : string, integer, list(integer) -> list(list(string))
Daniel@0: def csv_columns(filename,ncols,columns):
Daniel@0:     def getter(i): return lambda r:r[i]
Daniel@0:     return csv_map_columns(filename,ncols,map(getter,columns))
Daniel@0: 
Daniel@0: # returns selected columns of CSV, one list per column, with
Daniel@0: # a function supplied for converting one row of strings to a row of data
Daniel@0: #
Daniel@0: # csv_map_columns : string, integer, list(list(string)->A) -> list(list(A))
Daniel@0: def csv_map_columns(filename,ncols,sels):
Daniel@0:     ii=range(0,len(sels))
Daniel@0:     data=[[] for i in ii]
Daniel@0:     def append_columns(row):
Daniel@0:         for i in ii: data[i].append(sels[i](row))
Daniel@0:     csv_for_each(filename,ncols,append_columns)
Daniel@0: 
Daniel@0:     return data