在两个单词之间拆分字符串

Question

The following string

text = 'FortyGigE1/0/53\r\nCurrent state: DOWN\r\nLine protocol state: DOWN\r\n\r\nFortyGigE1/0/54\r\nCurrent state: DOWN\r\nLine protocol state: DOWN\r\n\r\n'

should be split into this:

output = [
    'FortyGigE1/0/53\r\nCurrent state: DOWN\r\nLine protocol state: DOWN\r\n\r\n',
    'FortyGigE1/0/54\r\nCurrent state: DOWN\r\nLine protocol state: DOWN\r\n\r\n'
]

The delimiters should not be deleted after the splitting.

delimiters = '(GigabitEthernet\d*/\d*/\d*\s.*|FortyGigE\d*/\d*/\d*\s.*)'

I tried to do this:

output = re.split(delimiters, text)

But my output will be this, with many more splits than I expected:

['',
 'FortyGigE1/0/53\r', '\nCurrent state: DOWN\r\nLine protocol state: DOWN\r\n\r\n',
 'FortyGigE1/0/54\r', '\nCurrent state: DOWN\r\nLine protocol state: DOWN\r\n\r\n']

Answer 1

At least with your example, you can do:

>>> re.split(r'(?<=DOWN\r\n\r\n)(?=FortyGigE)', text)
['FortyGigE1/0/53\r\nCurrent state: DOWN\r\nLine protocol state: DOWN\r\n\r\n',
 'FortyGigE1/0/54\r\nCurrent state: DOWN\r\nLine protocol state: DOWN\r\n\r\n']

Comparing to your stated desired output:

>>> output==re.split(r'(?<=DOWN\r\n\r\n)(?=FortyGigE)', text)
True

It works by using a zero width lookback (?<=DOWN\\r\\n\\r\\n) and a zero width lookahead (?=FortyGigE) as the point to split.

Here is a regex101 demo ; the \\r are removed since they are not supported on that platform.

Answer 2

your tip gave me the solution for my problem. Here the excerpt of my script:

f = open(file, "r")
content = f.read()
f.close()
#
# This deliminator is only an example. The interface names are much longer
deliminators = r'(?=\nBridge-Aggregation|\nHundredGigE|\nFortyGigE|\nTen-GigabitEthernet)'
#
dev_interfaces = re.split(deliminators, content)
max_interfaces = len(dev_interfaces)
# Delete the beginning Linefeed (\n) of each interface
dev_interfaces[index] = dev_interfaces[index].lstrip('\n')