This is my original .txt data:
HKEY_CURRENT_USER\SOFTWARE\7-Zip
HKEY_CURRENT_USER\SOFTWARE\AppDataLow
HKEY_CURRENT_USER\SOFTWARE\Chromium
HKEY_CURRENT_USER\SOFTWARE\Clients
HKEY_CURRENT_USER\SOFTWARE\CodeBlocks
HKEY_CURRENT_USER\SOFTWARE\Discord
HKEY_CURRENT_USER\SOFTWARE\Dropbox
HKEY_CURRENT_USER\SOFTWARE\DropboxUpdate
HKEY_CURRENT_USER\SOFTWARE\ej-technologies
HKEY_CURRENT_USER\SOFTWARE\Evernote
HKEY_CURRENT_USER\SOFTWARE\GNU
And I need to have a new file where the new lines contain only part of those strings, like:
7-Zip
AppDataLow
Chromium
Clients
...
how to do it in python?
Try this:
## read file content as string
with open("file.txt", "r") as file:
string = file.read()
## convert each line to list
lines = string.split("\n")
## write only last part after "\" in each line
with open("new.txt", "w") as file:
for line in lines:
file.write(line.split("\\")[-1] + "\n")
One approach would be to read the entire text file into a Python string. Then use split on each line to find the final path component.
with open('file.txt', 'r') as file:
data = file.read()
lines = re.split(r'\r?\n', data)
output = [x.split("\\")[-1] for x in lines]
# write to file if desired
text = '\n'.join(output)
f_out = open('output.txt', 'w')
f_out.write(text)
f_out.close()
I would like to iterate over a file and remove a series of lines that match a given regex. I have the script below but it only removes the 1st matching line/regex. How can i iterate through the file to get it to work?
import glob
import re
read_files = glob.glob("*.agr")
with open("out.txt", "w") as outfile:
for f in read_files:
with open(f, "r") as infile:
outfile.write(infile.read())
with open("out.txt", "r") as file:
filedata = file.read()
filedata = re.sub(r'#time\s+residue\s+[0-9]\s+Total', '', filedata)
with open("out.txt", "w") as file:
file.write(filedata)
Thanks
I solved the issue, i needed to modify the regex to specify >= 1 digit as follows: #time\s+residue\s+[0-9]+\s+Total. Previously the + sign in the regex was absent.
I have the following code, where I read an input list, split it on its backslash, and then append the variable evid to the evids array. Next, I open a file called evids.txt and write the evids to that file. How do I speed up/reduce the number of lines in this code? Thanks.
evids = []
with open('evid_list.txt', 'r') as infile:
data = infile.readlines()
for i in data:
evid = i.split('/')[2]
evids.append(evid)
with open('evids.txt', 'w') as f:
for i in evids:
f.write("%s" % i)
with open('evid_list.txt', 'r') as infile, open('evids.txt', 'w') as ofile:
for line in infile:
ofile.write('{}\n'.format(line.split('/')[2]))
I have a file 'master.sql' that contains:
a.b.c
d.e.f
g.h.i
and I want to write on 'databases.sql' just the first letters, like this:
a
d
g
Here is my code, but returns just the last letter, the 'g'.
with open ('master.sql', 'r') as f:
for line in f:
x=(line.split('.')[0])
with open('databases.sql', 'w') as f:
f.write(str(x))
How can I fix this?
You'll need to write your data as you read it, otherwise you're not going to be able to do what you want. Fortunately, with allows you to open multiple files concurrently. This should work for you.
with open ('master.sql', 'r') as f1, open('databases.sql', 'w') as f2:
for line in f1:
f2.write(line.split('.')[0] + '\n')
Don't forget to write a newline, because file.write doesn't add one automatically.
Using list:
x = []
with open('master.sql', 'r') as f:
for line in f.readlines():
x.append(line.split('.')[0])
with open('databases.sql', 'w') as f:
for word in x:
f.write(str(word)+'\n')
The variable x receives all values, but each loop overwrite the last value. Hence, the result is 'g'.
To save all values you can do like this:
lst = []
with open ('master.sql', 'r') as f:
for line in f:
lst.append(line.split('.')[0])
x = '\n'.join(lst)
with open('databases.sql', 'w') as f:
f.write(x)
So far I have this code:
f = open("text.txt", "rb")
s = f.read()
f.close()
f = open("newtext.txt", "wb")
f.write(s[::-1])
f.close()
The text in the original file is:
This is Line 1
This is Line 2
This is Line 3
This is Line 4
And when it reverses it and saves it the new file looks like this:
4 eniL si sihT 3 eniL si sihT 2 eniL si sihT 1 eniL si sihT
When I want it to look like this:
This is line 4
This is line 3
This is line 2
This is line 1
How can I do this?
You can do something like:
with open('test.txt') as f, open('output.txt', 'w') as fout:
fout.writelines(reversed(f.readlines()))
read() returns the whole file in a single string. That's why when you reverse it, it reverses the lines themselves too, not just their order. You want to reverse only the order of lines, you need to use readlines() to get a list of them (as a first approximation, it is equivalent to s = f.read().split('\n')):
s = f.readlines()
...
f.writelines(s[::-1])
# or f.writelines(reversed(s))
f = open("text.txt", "rb")
s = f.readlines()
f.close()
f = open("newtext.txt", "wb")
s.reverse()
for item in s:
print>>f, item
f.close()
The method file.read() returns a string of the whole file, not the lines.
And since s is a string of the whole file, you're reversing the letters, not the lines!
First, you'll have to split it to lines:
s = f.read()
lines = s.split('\n')
Or:
lines = f.readlines()
And your method, it is already correct:
f.write(lines[::-1])
Hope this helps!
There are a couple of steps here. First we want to get all the lines from the first file, and then we want to write them in reversed order to the new file. The code for doing this is as follows
lines = []
with open('text.txt') as f:
lines = f.readlines()
with open('newtext.txt', 'w') as f:
for line in reversed(lines):
f.write(line)
Firstly, we initialize a variable to hold our lines. Then we read all the lines from the 'test.txt' file.
Secondly, we open our output file. Here we loop through the lines in reversed order, writing them to the output file as we go.
A sample using list so it will be much easier:
I'm sure there answer that are more elegant but this way is clear to understand.
f = open(r"c:\test.txt", "rb")
s = f.read()
f.close()
rowList = []
for value in s:
rowList.append(value + "\n")
rowList.reverse()
f = open(r"c:\test.txt", "wb")
for value in rowList:
f.write(value)
f.close()
You have to work line by line.
f = open("text.txt", "rb")
s = f.read()
f.close()
f = open("newtext.txt", "wb")
lines = s.split('\n')
f.write('\n'.join(lines[::-1]))
f.close()
Use it like this if your OS uses \n to break lines
f = open("text.txt", "rb")
s = f.read()
f.close()
f = open("newtext.txt", "wb")
f.write(reversed(s.split("\n")).join("\n"))
f.close()
Main thing here is reversed(s.split("\n")).join("\n").
It does the following:
Split your string by line breaks - \n,
resulting an array
reverses the array
merges the array back with linebreaks \n to a string
Here the states:
string: line1 \n line2 \n line3
array: ["line1", "line2", "line3"]
array: ["line3", "line2", "line1"]
string: line3 \n line2 \n line1 \n
If your input file is too big to fit in memory, here is an efficient way to reverse it:
Split input file into partial files (still in original order).
Read each partial file from last to first, reverse it and append to output file.
Implementation:
import os
from itertools import islice
input_path = "mylog.txt"
output_path = input_path + ".rev"
with open(input_path) as fi:
for i, sli in enumerate(iter(lambda: list(islice(fi, 100000)), []), 1):
with open(f"{output_path}.{i:05}", "w") as fo:
fo.writelines(sli)
with open(output_path, "w") as fo:
for file_index in range(i, 0, -1):
path = f"{output_path}.{file_index:05}"
with open(path) as fi:
lines = fi.readlines()
os.remove(path)
for line in reversed(lines):
fo.write(line)