Initial commit

Solutions/5_5/reader.py

@@ -0,0 +1,43 @@
+# reader.py
+
+import csv
+import logging
+
+log = logging.getLogger(__name__)
+
+def convert_csv(lines, converter, *, headers=None):
+    rows = csv.reader(lines)
+    if headers is None:
+        headers = next(rows)
+
+    records = []
+    for rowno, row in enumerate(rows, start=1):
+        try:
+            records.append(converter(headers, row))
+        except ValueError as e:
+            log.warning('Row %s: Bad row: %s', rowno, row)
+            log.debug('Row %s: Reason: %s', rowno, row)
+    return records
+
+def csv_as_dicts(lines, types, *, headers=None):
+    return convert_csv(lines, 
+                       lambda headers, row: { name: func(val) for name, func, val in zip(headers, types, row) })
+
+def csv_as_instances(lines, cls, *, headers=None):
+    return convert_csv(lines,
+                       lambda headers, row: cls.from_row(row))
+
+def read_csv_as_dicts(filename, types, *, headers=None):
+    '''
+    Read CSV data into a list of dictionaries with optional type conversion
+    '''
+    with open(filename) as file:
+        return csv_as_dicts(file, types, headers=headers)
+
+def read_csv_as_instances(filename, cls, *, headers=None):
+    '''
+    Read CSV data into a list of instances
+    '''
+    with open(filename) as file:
+        return csv_as_instances(file, cls, headers=headers)
+