CSV data padding

csvpadding.py

# encoding: utf-8
# Usage: `pad_csv(«uneven CSV data»)` -> «padded CSV data»

try:
    from functools import reduce
except ImportError:
    pass

segments = lambda line: len(line.split(','))

max_segments = lambda csv_data: reduce(
    lambda line_segments, next_line: max(line_segments, segments(next_line)),
    csv_data.splitlines(), 0)

pad_line = lambda line, padding: line + ',' + ','.join('''""''' for idx in range(padding))

pad_segments = lambda csv_data, padding: map(
    lambda line: segments(line) < padding and pad_line(line, padding - segments(line)) or line,
    csv_data.splitlines())

pad_csv = lambda csv_data: '\n'.join(pad_segments(csv_data, max_segments(csv_data)))

Now a part of CLU: https://github.com/fish2000/CLU/blob/master/clu/csv.py