comparison dml-cla/python/csvutils.py @ 0:718306e29690 tip

commiting public release

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