I edit the sample
Here is sample textfile.txt
-------!@#$-------
text line1
text line2
-------!@#$-------
dummy text dummy test dummy test
dummy test dummy test dummy test
-------!@#$-------
text line3
text line4
-------!@#$-------
I want to parse
"text line 1\n text line 2" → array [0]
"text line 3\n text line 4" → array [1]
How should I source coding in python?
Python's groupby() function is good for doing this:
from itertools import groupby
with open('input.txt') as f_input:
data = [list(g) for k, g in groupby(f_input, lambda x: not x.startswith("-------!@#$-------")) if k]
data = [''.join(x) for x in data]
print data
Giving you data holding:
['text line1\ntext line2\n', 'text line3\ntext line4\n']
The first list comprehension reads the file grouping lines that do not start with your line separator. This results in data holding:
[['text line1\n', 'text line2\n'], ['text line3\n', 'text line4\n']]
Next, a second list comprehension is used to join back the multiple lines.
So:
data[0] --> 'text line1\ntext line2\n'
data[1] --> 'text line3\ntext line4\n'
To parse out sections containing certain words, the second list comprehension could be replaced with this one:
data = [''.join(x) for x in data if 'dummy test' not in ''.join(x)]
data = [''.join(x) for x in data if 'dummy test' not in ''.join(x)]You can split on your delimiter and then cleanup the individual array elements
sample = '''-------!@#$-------
text line1
text line2
-------!@#$-------
text line3
text line4
'''.split('-------!@#$-------')
>> ['', '\ntext line1\ntext line2\n', '\ntext line3\ntext line4\n']
Cleanup looks something like this
print [x.strip() for x in sample if len(x) > 0]
>> ['text line1\ntext line2', 'text line3\ntext line4']
Given a file or list of strings such as:
>>> sample = '''\
-------!@#$------- # line 0 --> 0th in group --> skip
text line1 # line 1 --> 1st in group --> save in "last"
text line2 # line 2 --> 2nd in group --> add to "last"
-------!@#$------- # line 3 --> 0th in group --> skip
text line3 # line 4 --> 1st in group --> save in "last"
text line4 # line 5 --> 2nd in group --> add to "last"
'''.splitlines(keepends=True)
The easiest way to accumulate across multiple lines is to count the lines and take different actions depend on whether it is the 0th line in the group should be skipped, the 1st line in the group should be saved in a variable, or the 2nd line in the group which should be aggregated with the one saved in the variable:
>>> array = []
>>> last = ''
>>> for i, line in enumerate(sample):
if i % 3 == 1:
last = line
elif i % 3 == 2:
line = last + line
array.append(line)
>>> array
[' text line1\n text line2\n', ' text line3\n text line4\n']
This should give you a required list List of lines for given filename
with open('textfile.txt','r') as f:
lines = f.read()
result=lines.split('-------!@#$-------')
You can split with the separator line. Then filter the non empty string in list. With that result, strip the trailing new line.
That is,
with open('textfile.txt','r') as f:
print map(str.strip,filter(None,f.read().split('-------!@#$-------')))
For the updated text file that has dummy contents you can use lambda function!
with open('textfile.txt','r') as f:
print map(str.strip,filter(lambda i: i and 'dummy' not in i,f.read().split('-------!@#$-------')))
Output:
['text line1\ntext line2', 'text line3\ntext line4']
Hope it helps!
