Formats a list of dicts into a textual table.

easy_table.py

#!/usr/bin/env python

# Ported from clojure.pprint/print-table

from StringIO import StringIO

def format_row(headers, row, fmts):
  out = []
  for col, fmt in zip([row[k] for k in headers], fmts):
    out.append(fmt % col)
  return " | ".join(out)

def table(rows, headers=None):
  if headers is None:
    headers = rows[0].keys()

  widths = [max(len(str(k)), *[len(str(r[k])) for r in rows]) for k in headers]
  fmts = [''.join(["%-", str(w), "s"]) for w in widths]
  header = format_row(headers, dict(zip(headers, headers)), fmts)
  bar = "=" * len(header)

  buffer = StringIO()
  buffer.write(bar + "\n")
  buffer.write(header + "\n")
  buffer.write(bar + "\n")
  for row in rows:
    buffer.write(format_row(headers, row, fmts) + "\n")
  buffer.write(bar)

  return buffer.getvalue()

if __name__ == "__main__":
  print "== Example ==\n"

  data = [
    { "name": "John", "age": 25 },
    { "name": "Michael", "age": 30},
    { "name": "Jim", "age": 16 }
  ]
  print table(data, headers=["name", "age"])