I am reading a text file which has data like this string input: String input :

string = """unwanted strings

/start INPUT_DATA
    input_data_Name_One  input_data_Name_two
/end INPUT_DATA
unwanted string
/start OUTPUT_DATA 
    ouput_data_Name_One  ouput_data_Name_Two 
/end OUTPUT_DATA
unwanted string
/start LOC_DATA   
    loc_Data_Name_One  loc_data_Name_Two  loc_data_Name_Three
/end LOC_DATA
unwanted string
/start LOC_THING   
    no_Need_One no_Need_Two  no_Need_Three
/end LOC_THING

unwanted strings"""

matches = re.findall('start(.*?)end', string, re.DOTALL)

I tried with many expressions but newline,special charecters giving errors how to escape it.

expected output:

 ['input_data_Name_One' ,'input_data_Name_two','ouput_data_Name_One','ouput_data_Name_Two','loc_Data_Name_One','loc_data_Name_Two','loc_data_Name_Three']

CodePudding user response：

You can use this findall split approach:

import re

string = """unwanted strings

/start INPUT_DATA
    input_data_Name_One  input_data_Name_two
/end INPUT_DATA
unwanted string
/start OUTPUT_DATA 
    ouput_data_Name_One  ouput_data_Name_Two
/end OUTPUT_DATA
unwanted string
/start LOC_THING
          no_Need_One no_Need_Two  no_Need_Three
/end LOC_THING

/start LOC_DATA   
    loc_Data_Name_One  loc_data_Name_Two  loc_data_Name_Three
/end LOC_DATA

unwanted strings"""

print ( [s.split() for s in re.findall(r'/start .*_DATA\s ((?:. \n) ?)/end ', string)] )

Output:

[['input_data_Name_One', 'input_data_Name_two'], ['ouput_data_Name_One', 'ouput_data_Name_Two'], ['loc_Data_Name_One', 'loc_data_Name_Two', 'loc_data_Name_Three']]

Here:

• We use findall to match 1 lines between /start line that ends with _DATA and another line with /end keywords.
• Then we use split to split matches on whitespaces.

CodePudding user response：

list(filter(None,re.findall(r'(\w _[dD]ata_[_\w] |)', string )))

['input_data_Name_One', 'input_data_Name_two', 'ouput_data_Name_One', 'ouput_data_Name_Two', 'loc_Data_Name_One', 'loc_data_Name_Two', 'loc_data_Name_Three']Name_Three']