Regex for replace msgstr in PO file data using python

Question

I have list content = ['x', 'y', 'z']

.po file content:

msgid 'abc'
msgstr ''

msgid 'def'
msgstr ''

msgid 'ghi'
msgstr ''

I need output like below:

msgid 'abc'
msgstr 'x'

msgid 'def'
msgstr 'y'

msgid 'ghi'
msgstr 'z'

Edit:

with io.open('file.po, 'r', encoding='utf-8') as pofile:
    filedata = pofile.read()

So filedata has all content of PO file

Answer 1

The solution using built-in iter() function and re.sub() function:

import re

content = ['x', 'y', 'z']
po_data = '''
msgid 'abc'
msgstr ''

msgid 'def'
msgstr ''

msgid 'ghi'
msgstr ''
'''

content_it = iter(content)    # constructing iterator object from iterable
result = re.sub(r'(msgstr )\'\'', lambda m: "%s'%s'" % (m.group(1), next(content_it)), po_data)

print(result)

The output:

msgid 'abc'
msgstr 'x'

msgid 'def'
msgstr 'y'

msgid 'ghi'
msgstr 'z'