Find a String with Python?

Question

i am searching fo a way to get a Hex Number from a line.

It is a bigger file and i can find the number this way:

The line starts with ".text" (it is the first one which starts with .text). This line contains 3 HexNumbers and i need everytime the second one.

The Problem is that the positions of the numbers are not everytime the same, also the length is not everytime the same.

The line looks like

.text        0x00000        0x4e32     0x11000000

between the numbers there are several spaces, not same everytime.

How can i get and save the 0x4e32 ?

I tried to start like this:

for num, line in enumerate(mapfile, 1):
    line = line.rstrip()
    if line.startswith('.text '):
        foundLine = line
        strCheck = "0x"
        lineNumber = num
        col = foundLine.find(strCheck)+1
        print lineNumber, col           

        index = 0
        maxLen = 60
        while index < len(line):
            index = line.find('0x', index)
            if index == -1:
                break
        print('Code Size found at', index)
        index += 2

Burhan Khalid · Accepted Answer · 2015-02-17 12:22:06Z

1

Once a line starts with .text, split it and the third item will be your target value:

with open('large_file.txt') as f:
   for number,line in enumerate(f):
       if line.startswith('.text'):
           bits = line.split()
           try:
              print('Found at line # {} - {}'.format(number, bits[2]))
           except IndexError:
              print('Malformed line: {}'.format(line))

answered Feb 17, 2015 at 12:22

Burhan Khalid

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score 1 · Accepted Answer · 2015-02-17 12:31:10Z

1

The .split() method without an argument splits a string at whitespace. This means that any number of spaces will do, and the behavior will be the same with one or a hundred spaces between the words. Then just regularly access with the index of the word you want.

e.g.

words = line.split()
words[2]

edited Feb 17, 2015 at 12:31

answered Feb 17, 2015 at 12:20

user1425689

Comments

vks · Accepted Answer · 2015-02-17 12:17:37Z

0

import re
p = re.compile(r'^\.text\s*\S+\s*(\S+)', re.MULTILINE)
test_str = ".text 0x00000 0x4e32 0x11000000"

re.findall(p, test_str)

You can iterate over lines apply this regex to each line and get your result.If the file is not big then you can load the while file in memory and then appy regex to get results in one go.

answered Feb 17, 2015 at 12:17

vks

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