object patch

Solutions/9_5/porty-app/porty/tableformat.py

@@ -0,0 +1,81 @@
+# tableformat.py
+
+class TableFormatter:
+    def headings(self, headers):
+        '''
+        Emit the table headers
+        '''
+        raise NotImplementedError()
+
+    def row(self, rowdata):
+        '''
+        Emit a single row of table data
+        '''
+        raise NotImplementedError()
+
+class TextTableFormatter(TableFormatter):
+    '''
+    Output data in plain-text format.
+    '''
+    def headings(self, headers):
+        for h in headers:
+            print(f'{h:>10s}', end=' ')
+        print()
+        print(('-'*10 + ' ')*len(headers))
+
+    def row(self, rowdata):
+        for d in rowdata:
+            print(f'{d:>10s}', end=' ')
+        print()
+
+class CSVTableFormatter(TableFormatter):
+    '''
+    Output data in CSV format.
+    '''
+    def headings(self, headers):
+        print(','.join(headers))
+
+    def row(self, rowdata):
+        print(','.join(rowdata))
+
+class HTMLTableFormatter(TableFormatter):
+    '''
+    Output data in HTML format.
+    '''
+    def headings(self, headers):
+        print('<tr>', end='')
+        for h in headers:
+            print(f'<th>{h}</th>', end='')
+        print('</tr>')
+
+    def row(self, rowdata):
+        print('<tr>', end='')
+        for d in rowdata:
+            print(f'<td>{d}</td>', end='')
+        print('</tr>')
+
+class FormatError(Exception):
+    pass
+
+def create_formatter(name):
+    '''
+    Create an appropriate formatter given an output format name
+    '''
+    if name == 'txt':
+        return TextTableFormatter()
+    elif name == 'csv':
+        return CSVTableFormatter()
+    elif name == 'html':
+        return HTMLTableFormatter()
+    else:
+        raise FormatError(f'Unknown table format {name}')
+
+def print_table(objects, columns, formatter):
+    '''
+    Make a nicely formatted table from a list of objects and attribute names.
+    '''
+    formatter.headings(columns)
+    for obj in objects:
+        rowdata = [ str(getattr(obj, name)) for name in columns ]
+        formatter.row(rowdata)
+