Python Dialogs

  Me (indented by 2) and the chatbot (flush left). Lines lengths > 72!

  Assume you have an expression "s.replace('a','b').replace('c','d').
  replace('e','f').replace('g','h')". Its value is a string which
  is the value of s, but with "a" replaced by "b", "c" replaced by
  "d", "e" replaced by "f" and "g" replaced by "h". How to modify
  this expression, so that "a", "c", "e", and "g", respectively,
  are replaced only if they are words (but not parts of words)?

import re

s.replace(r"\ba\b", "b").replace(r"\bc\b", "d").replace(r"\be\b", "f").replace(r"\bg\b", "h")

  No. "replace" will not use regular expressions, even if you write
  "import re".

import re

s = re.sub(r"\ba\b", "b", s)
s = re.sub(r"\bc\b", "d", s)
s = re.sub(r"\be\b", "f", s)
s = re.sub(r"\bg\b", "h", s)

  Now you give me a sequence of four statements, but I need an
  expression!

s = re.sub(r"\ba\b", "b", re.sub(r"\bc\b", "d", re.sub(r"\be\b", "f", re.sub(r"\bg\b", "h", s))))

  Yeah, that's an expression, but it's kind of nested I guess.
  Can you write another expression with less nesting?

s = re.sub(r"\ba\b|\bc\b|\be\b|\bg\b", lambda x: {"a": "b", "c": "d", "e": "f", "g": "h"}[x.group()], s)

  Nice idea! Only drawback is that to add another word, you gotta
  modify in two places.

replacements = {"a": "b", "c": "d", "e": "f", "g": "h"}
s = re.sub(r"\b(" + "|".join(replacements.keys()) + r")\b", lambda x: replacements[x.group()], s)

  PS: This is for the script I use to send posts. So if you do not
  see "trying to" (5 letters: "t-r-y-n-a") here, it kind of worked!