soln3_5.md

Exercise 3.5 - Solution

# tableformat.py

def print_table(records, fields, formatter):
    formatter.headings(fields)
    for r in records:
        rowdata = [getattr(r, fieldname) for fieldname in fields]
        formatter.row(rowdata)

class TableFormatter:
    def headings(self, headers):
        raise NotImplementedError()

    def row(self, rowdata):
        raise NotImplementedError()

class TextTableFormatter(TableFormatter):
    def headings(self, headers):
        print(' '.join('%10s' % h for h in headers))
        print(('-'*10 + ' ')*len(headers))
    
    def row(self, rowdata):
        print(' '.join('%10s' % d for d in rowdata))

class CSVTableFormatter(TableFormatter):
    def headings(self, headers):
        print(','.join(headers))

    def row(self, rowdata):
        print(','.join(str(d) for d in rowdata))

class HTMLTableFormatter(TableFormatter):
    def headings(self, headers):
        print('<tr>', end=' ')
        for h in headers:
            print('<th>%s</th>' % h, end=' ')
        print('</tr>')

    def row(self, rowdata):
        print('<tr>', end=' ')
        for d in rowdata:
            print('<td>%s</td>' % d, end=' ')
        print('</tr>')

def create_formatter(name):
    if name == 'text':
        formatter_cls = TextTableFormatter
    elif name == 'csv':
        formatter_cls = CSVTableFormatter
    elif name == 'html':
        formatter_cls = HTMLTableFormatter
    else:
        raise RuntimeError('Unknown format %s' % name)
    return formatter_cls()

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