# Equations with Regular Expressions

Harvey Thomas hst at empolis.co.uk
Wed Feb 27 17:47:31 CET 2002

```try the following (extended to allow for x^n)

import re

def dosub(mg):
if mg.group(1):
return '%s*(%s**%s)' % (mg.group(1), mg.group(2), mg.group(3))
else:
return '%s**%s' % (mg.group(2), mg.group(3))

regex = re.compile('(\d*)([a-zA-Z])\^(\d+)')
print regex.sub(dosub, '2x^3-2x^2+15-x^4*6')

-----Original Message-----
From: Alves, Carlos Alberto - Coelce [mailto:calves at coelce.com.br]
Sent: 27 February 2002 10:33
To: python-list at python.org
Subject: Equations with Regular Expressions

Hi everybody,
Could someone of you give me and example of how can I translate '2x^3-2x^2+15' into '2*(x**3)-2*(x**2)+15' using regular expressions.
Carlos Alberto
COELCE/DPRON-Departamento de Projetos e Obras Norte
Fone: 677- 2228
e-mail: calves at coelce.com.br
\|||/
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```