Develop Reference

How to assign variable for every line in txt seperately in Python?

I have a text file that with multiple lines and I'm trying to assign turn every line into a string and assign them into a variable separately. The code looks something like this at the moment:
with open('config.txt', 'r') as f:
file_name = ''.join(f.readlines()[0:1])
Runstart = ''.join(f.readlines()[1:2])
Runend = ''.join(f.readlines()[2:3])
But it doesn't read anything after the first line. What am I doing wrong here and how do I fix it? The goal is to give a name for every line. Alternative methods are welcomed.
Thanks.

You don't need all these slices and indices. Just use readline:
with open('config.txt', 'r') as f:
file_name = f.readline()
Runstart = f.readline()
Runend = f.readline()

You can treat the file as an iterator.
from itertools import islice
with open('config.txt', 'r') as f:
file_name, Runstart, Runend = (x.rstrip() for x in islice(f, 3))

not sure if this helps but this is what I understand from your question:
with open('config.txt', 'r') as f:
for line in f:
thisList = line.split(' ')
string = ''
file_name = thisList[0]
Runstart = thisList[1]
Runend = thisList[2]
print(file_name, Runstart, Runend)

python nested for loop is iterate only once

i created a program to compare two text file , and identify duplicate and unique items
but first for loop is running only once after that it exit without iterating second item in the file. if any one can help please do.
f1 = open("file1.txt","r")
f2 = open("file2.txt","r")
duplicate = open("duplicate_ip.txt", "w")
unique = open("unique_ip.txt", "w")
for x in f1:
for y in f2:
if x == y:
duplicate.write(y)
else:
unique.write(x)
file1.txt contains following
192.168.1.1
192.168.10.2
192.168.56.5
192.16.10.2
192.168.5.5
file2.txt contain following
192.168.1.2
10.10.10.0
10.10.10.11
192.168.11.111
127.0.0.1
172.16.31.5

If you want f1 and f2 to be list of strings, then please use readlines() method. Also don't forget to close files (at least the ones you write to).
f1 = open("file1.txt", "r").readlines()
f2 = open("file2.txt", "r").readlines()
duplicate = open("duplicate_ip.txt", "w")
unique = open("unique_ip.txt", "w")
for x in f1:
for y in f2:
if x == y:
duplicate.write(y)
else:
unique.write(x)
f1.close()
f2.close()
duplicate.close()
unique.close()
But there is a much simple way to manage file IO sessions with use of context manager. Your code will then will be looking something like this
with open("file1.txt", "r") as f1, \
open("file2.txt", "r") as f2, \
open("duplicate_ip.txt", "w") as duplicate, \
open("unique_ip.txt", "w") as unique:
f1_lines = f1.readlines()
f2_lines = f2.readlines()
for x in f1_lines:
for y in f2_lines:
if x == y:
duplicate.write(y)
else:
unique.write(x)

Solution with set operation & (intersection) and ^ (XOR operation)
f1_ip = set(open("file1.txt","r"))
f2_ip = set(open("file2.txt","r"))
with open("duplicate_ip.txt", "w") as duplicate:
for ip in f1_ip & f2_ip:
duplicate.write(ip)
with open("unique_ip.txt", "w") as unique:
for ip in f1_ip ^ f2_ip:
unique.write(ip)

you can write like this:
with open("file1.txt", "r") as f1:
data1 = set()
for line in f1.readlines():
data1.add(line.strip('\n'))
with open("file2.txt", "r") as f2:
data2 = set()
for line in f2.readlines():
data2.add(line.strip('\n'))
unique_list = data1.difference(data2)
duplicate_list = data1.intersection(data2)
with open("duplicate_ip.txt", "w") as duplicate:
for ip in duplicate_list:
duplicate.write(ip+ "\n")
with open("unique_ip.txt", "w") as unique:
for ip in unique_list:
unique.write(ip+ "\n")

To answer the question, you're opening the file, but not reading the lines, so you're not actually iterating over the file.
Couple comments:
you should try to open files using with so you don't accidentily leave them open
this still wont work, as the last line won't have a \n so you should probably remove them using .replace
you're only checking one way, any ips in file2 that aren't in file 1 wont be found this way, not sure if that's what you want
there are faster ways to check which items are the same in two lists and which are unique
To solve the main issue:
with open("file1.txt","r") as f1:
data1 = f1.readlines()
with open("file2.txt","r") as f2:
data2 = f2.readlines()
with open("duplicate_ip.txt", "w") as duplicate, \
open("unique_ip.txt", "w") as unique:
for x in data1:
for y in data2:
if x == y:
duplicate.write(y)
else:
unique.write(x)

Comparing two txt files and generate a new txt file with the strings that are only in one

I have two txt files with a string per line. I want to compare txt file 1 with txt file 2 and generate a new file with all the strings that are in 2 but not in 1.
I tried something rather simple:
file1 = open("file1.txt", "r")
file2 = open("file2.txt", "r")
for word in file2:
if word not in file1:
print(word)
What this code does, it gives me all the strings from file2 if there is ANY string not in 1.
**file1:**
this
is
a
word
**file2:**
this
is
a
totally
different
word
What I would expect is only the string "totally" and "different". But I get all the strings from file2.

open() function returns file object, not string that is inside that file. In order to read text inside you'd need to read after you open file. Also it's a good habit to close files always when you open them. That's why personally I prefer to use command with open('file1.txt', 'r') as file1: to make sure that after I'm done with that file it's always closed and I don't have to run close method explicitly. It would look like this:
with open('file1.txt', 'r', encoding='utf8') as file1:
with open('file2.txt', 'r', encoding='utf8') as file2:
text1 = file1.read()
text2 = file2.read()
words1 = text1.split('\n')
words2 = text2.split('\n')
unique_words = list(filter(lambda w2: w2 not in words1, words2))
for word in unique_words:
print(word)

You can use the .readlines() function which will convert all the lines in the text file to an element in a list or it will generate a list of the those lines.
file1 = open("file1.txt", "r")
file2 = open("file2.txt", "r")
f1=file1.readlines()
f2=file2.readlines()
for word in f2:
if word not in f1:
print(word)

How about this:-
FILES = ['file1.txt', 'file2.txt']
SETS = []
for _file in FILES:
with open(_file) as infile:
_lines = [line.strip() for line in infile.readlines()]
SETS.append(set(_lines))
print(SETS[1] - SETS[0])

Try with this solution:
file1 = open("file1.txt", "r")
file2 = open("file2.txt", "r")
word1 = [x for x in file1]
word2 = [x for x in file2]
words = [x.strip("\n") for x in word2 if x not in word1]
Output:
['totally', 'different']
I wrote x.strip("\n") because my example file contain a word for each row.

Having next items in a list while we run a for loop

I'm a beginner in python and I'm writing a code which I'm trying to check if I find a specific item I can check some items before and if I can print the current value.
I wrote this code but I can't get the problem:
import re
file1 = open('A.txt', 'r')
file2 = open('B.txt', 'w')
line = file1.readlines()
for index, line in enumerate(file1):
match = re.search(r'R', line)
if match:
for a in range(index, index+2):
same = re.search(r'T', line.next())
if same:
file2.writelines(line)
file2.close()
file1.close()

You weren't very clear with your question, but I suspect that you're trying to do something like this:
You want to make sure that line1 from fine A.txt goes into file B.txt if it has R character in it, and it is followed by a line that has T character in it. Here's a solution for that problem.
import re
file1 = open('A.txt', 'r')
file2 = open('B.txt', 'w')
last_line = file1.readline()
while (current_line := file1.readline()):
match_last = re.search(r'R', last_line)
match_current = re.search(r'T', current_line)
if match_last and match_current:
file2.writelines(last_line)
last_line = current_line
file2.close()
file1.close()

How to delete lines from a text file?

How can I make this work to delete values from my txt file? I have an 11 line file of 4 digit numbers, I can add but am stuck on deleting.
def delete_file(string_in):
print("deleted_from_file")
with open('test.txt', 'a+') as f:
d = f.readlines()
f.seek(11)
for i in d:
if i != " item = {} ":
f.write(i)
f.close()

a+ mode means to write at the end of the file. So the seek has no effect, it always writes the lines after all the existing lines.
It would be easier to just open the file separately for reading and writing. Otherwise you also need to truncate the file after all the writes.
BTW, you don't need to use f.close() when you use with -- it automatically closes (that's the whole point).
The lines returned by readlines() end with newlines, you need to strip those off before comparing with the string.
def delete_file(string_in):
print("deleted_from_file")
with open('test.txt', 'r') as f:
d = f.readlines()
with open('test.txt', 'w') as f:
for i in d:
if i.rstrip('\n') != " item = {} ":
f.write(i)

You can store all the needed lines into a list using a list comprehension, and then write the lines into the file again after the file empties out:
def delete_file(string_in):
print("deleted_from_file")
with open('test.txt', 'r') as f:
d = [i for i in f if i.strip('\n') != " item = {} "]
with open('test.txt', 'w') as f:
f.write(''.join(d))