Regular expression syntax in python - regex

Question

I try to write a python scripts to analys a data txt.I want the script to do such things:
find all the time data in one line, and compare them.but this is my first time to write RE syntax.so I write a small script at 1st.
and my script is:
import sys
txt = open('1.txt','r')
a = []
for eachLine in txt:
a.append(eachLine)
import re
pattern = re.compile('\d{2}:\d{2}:\d{2}')
for i in xrange(len(a)):
print pattern.match(a[i])
#print a
and the output is always None.
my txt is just like the picture:
what's the problem? plz help me. thx a lot.
and my python is python 2.7.2.my os is windows xp sp3.

Answer 1

Didn't you miss one of the ":" in you regex? I think you meant
re.compile('\d{2}:\d{2}:\d{2}')
The other problems are:
First, if you want to search in the hole text, use search instead of match. Second, to access your result you need to call group() in the match object returned by your search.
Try it:
import sys
txt = open('1.txt','r')
a = []
for eachLine in txt:
a.append(eachLine)
import re
pattern = re.compile('\d{2}:\d{2}:\d{2}')
for i in xrange(len(a)):
match = pattern.search(a[i])
print match.group()
#print a

Answer 2

I think you're missing the colons and dots in your regex. Also try using re.search or re.findall instead on the entire text. Like this:
import re, sys
text = open("./1.txt", "r").read() # or readlines() to make a list of lines
pattern = re.compile('\d{2}:\d{2}:\d{2}')
matches = pattern.findall(text)
for i in matches:
print(i);