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Date: Thu, 4 Jun 2015 08:48:55 -0500
From: Tim Chase <python.list@tim.thechases.com>
To: Palpandi <palpandi111@gmail.com>
Cc: python-list@python.org
Subject: Re: Regular Expression
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Xref: csiph.com comp.lang.python:92054

On 2015-06-04 06:36, Palpandi wrote:
> This is the case. To split "string2" from "string1_string2" I am
> using re.split('_', "string1_string2", 1)[1].
> 
> It is working fine for string "string1_string2" and output as
> "string2". But actually the problem is that if a sting is
> "__string1_string2" and the output is "_string1_string2". It is
> wrong.

Why use regular expressions to split a string on a constant?

Try

  for input in [
      "string1_string2",
      "__string1_string2",
      ]:
    value = input.rsplit('_', 1)[-1]
    assert value == "string2"

-tkc