Changeset 5554 for workshop2010/trunk

Timestamp:

30 Sep 2010, 10:10:38 (14 years ago)

Author:

uli

Message:

Copy CSV file merger created last evening into repository.

File:

• workshop2010/trunk/src/grokworkshop/mergecsv.py (modified) (1 diff)

workshop2010/trunk/src/grokworkshop/mergecsv.py

@@ -3 +3 @@
 import csv
 
-input1 = """
-"""
-
-input2 = """
-"""
-
-
-def merge_csv_files():
+def merge_csv_files(csv_path1=None, csv_path2=None,
+                    wanted_headers=['id', 'student_id', 'name']):
     """Merge a file 'input1.csv' and 'input2.csv'.
     """
+    input1 = csv_path1
+    input2 = csv_path2
+
+    students_reader = csv.DictReader(open(input1, 'rb'))
+    payments_reader = csv.DictReader(open(input2, 'rb'))
+
+    result_writer = None
+
+    students = dict()
+    for student in students_reader:
+        # Read all students and store them under their respective id
+        students[student['id']] = student
+    for payment in payments_reader:
+        # Read all payments and lookup a matching student
+        student_id = payment['student_id']
+
+        if student_id not in students.keys():
+            # Oops, what happened?
+            print "STUDENT NOT FOUND: ", student_id
+            continue
+
+        student = students[student_id]
+        result_line = payment
+        result_line.update(student)
+        if result_writer is None:
+            # Create a CSV writer and ouput header line
+            result_writer = csv.DictWriter(open('result.csv', 'wb'), 
+                                           wanted_headers, 
+                                           extrasaction='ignore')
+            header_line = dict([(x, x) for x in wanted_headers])
+            result_writer.writerow(header_line)
+        result_writer.writerow(result_line)