Read all lines between two string

Question

I want to extact lines from an xml that are between from my xml. Here is an example:

<userData code="viPartListRailML" value="1">
            <partRailML s="0.0000000000000000e+00" id="0"/>
            <partRailML s="2.0000000000000000e+01" id="1"/>
            <partRailML s="9.4137883373059267e+01" id="2"/>
        </userData>

Here is my code, that I was trying:

import re

shakes = open("N:\SAJAT_MAPPAK\IGYULAVICS\/adhoc\pythonXMLread\probaxml\github_minta.xml", "r")
for x in shakes:
    if "userData" in x:
        print x
        continue
    if "/userData" in x:
        break

The problem is that it still gives back only the lines that contain <userData or </userData> How to modify it to get the lines between these two "words"

Answer 1

Assuming that there is one <userData> block in your file, your can extract lines within block by:

shakes = open("./file.xml", "r")
inblock = False
for x in shakes:
    if "/userData" in x:
        inblock = False
    if inblock:
        print(x)
    if "userData" in x:
        inblock = True

But read your file with a xml parser is more robust, like:

import xml.etree.ElementTree as ET

tree = ET.parse('file.xml')

for data in tree.getroot().iter('userData'):
    for child in data:
        print(ET.tostring(child))
        # or something else, eg:
        # print(child.tag)

BTW, use Python3 whenever possible, Python2 is retired.

Answer 2

Easy way is to add a variable, which tells if you are between those words:

shakes = open("N:\SAJAT_MAPPAK\IGYULAVICS\/adhoc\pythonXMLread\probaxml\github_minta.xml", "r")
t=False
for x in shakes:
    if t:
        print(x) # also /userdata -line is printed
    if "/userData" in x:
        t=False
    elif "userData" in x: # this matches /userData as well--> elif
        t=True

Answer 3

You can use itertools.dropwhile to reach the <userData part and then use itertools.takewhile to read until </userData :

import itertools as it

result = it.takewhile(
    lambda x: '</userData' not in x,
    it.dropwhile(
        lambda x: '<userData' not in x,
        text.splitlines()
    )
)
print('\n'.join(result))

If you want to skip the <userData element you can add itertools.islice :

result = it.takewhile(
    lambda x: '</userData' not in x,
    it.islice(it.dropwhile(
        lambda x: '<userData' not in x,
        text.splitlines()
    ), 1, None)
)
print('\n'.join(result))