# 0905.py
import re

testo='0123456789012345'
ris=re.search('4[856].[27]',testo)

print (ris)
# <_sre.SRE_Match object at 0xb7b77170>

print (ris.start(), ris.end())
# 4 8
print (testo[ris.start():ris.end()])
# 4567
print (ris.group())
# 4567
print (ris.re)
# <_sre.SRE_Pattern object at 0xb7c08708>
print (ris.string)
# 0123456789012345

#######################################

testo='Ferrara\nRoma\nFirenze\nPisa'

ris=re.search('',testo)
print (ris)
# <_sre.SRE_Match object at 0xb7b771e0>

ris=re.search('57',testo)
print (ris)
# None

ris=re.search('...$',testo)
if ris: print (ris.group())
# isa

ris=re.search('...$',testo,re.M)
if ris: print (ris.group())
# ara

ris=re.search('e.p',testo,re.I)
print (ris)
# None

ris=re.search('e.p',testo,re.S|re.I)
if ris: print (ris.group())
# e
# P