CODEWITHSUNDEEP
pythonpython-2.7
kitty
kitty

Reputation: 105

Search string and print from one line above to another search string in python

I have file like below (temp1 file):

Basket1
10 Pens I have in Packet1
20 Books I have in Packet1
30 Red pens I have in Packet1
End here
Basket1
10 apples I have in Packet2
20 Mangos I have in Packet2
30 oranges I have in Packet2.
End here

I have written below code it will search start line and end line and prints between lines including start and end lines.

start_line = "Pens I have"
end_line = "End here"
print_lines = False
with open('temp1' , 'r') as f:
    for line in f:
        line = line.strip()
        if (re.search(start_line, line)):
            print_lines = True
        if print_lines:
            temp = open("temp2", 'a')
            sys.stdout = temp
            print line
        if (re.search(end_line, line)):
            print_lines = False
            temp.close()
            sys.stdout = sys.__stdout__

Output I am getting:

10 Pens I have in Packet1
20 Books I have in Packet1
30 Red pens I have in Packet1
End here

I need help to print lines to file temp2 from above one line from start line to end line . Below is the expected output to file temp2.

Basket1
10 Pens I have in Packet1
20 Books I have in Packet1
30 Red pens I have in Packet1
End here

Upvotes: 1

Views: 572

Answers (2)

JkShaw
JkShaw

Reputation: 1947

Since you need Basket1 to be printed, your start_line has to be Basket1, and as after first line you need Pens I have i have used it as 'mid_line',

import sys
import re

start_line = "Basket1"
mid_line = "Pens I have"
end_line = "End here"
print_lines = False

start_index = None
start_data = None
temp = None

with open('temp1' , 'r') as f:
    for index, line in enumerate(f):
        line = line.strip()

        # Search for start_line, and store it's index and value
        if (re.search(start_line, line)):
            start_data = line
            start_index = index

        # If you find "Pens I have", and it's under start_line then store start_line
        if (re.search(mid_line, line)):
            if start_index + 1 == index:
                temp = open("temp2", 'a')
                sys.stdout = temp
                print start_data
                print_lines = True
        if print_lines:
            temp = open("temp2", 'a')
            sys.stdout = temp
            print line
        if (re.search(end_line, line)):
            print_lines = False
            if temp and hasattr(temp, 'read'):
                temp.close()
            sys.stdout = sys.__stdout__

Upvotes: 0

Taku
Taku

Reputation: 33714

You can use a regex to search your string, to use it for reading from and writing to file, you can do:

import re

with open('temp1' , 'r') as f1, open('temp2' , 'a') as f2:
    results = re.findall('\w+\n10 Pens I.*?End here', f1.read(), re.DOTALL)
    f2.writelines(results)

Example:

import re

s = '''Basket1
10 Pens I have in Packet1
20 Books I have in Packet1
30 Red pens I have in Packet1
End here
Basket1
10 apples I have in Packet2
20 Mangos I have in Packet2
30 oranges I have in Packet2.
End here'''

# use re.findall if you want to match multiple times
result = re.search('\w+\n10 Pens I.*?End here', s, re.DOTALL)

# only print(result) if using re.findall
print(result.group())

# output:

Basket1
10 Pens I have in Packet1
20 Books I have in Packet1
30 Red pens I have in Packet1
End here

Upvotes: 1

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