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How to replace two different lines of text?

I need to create a file that changes the date and name of a .txt, but I can only change one or the other with this code I found on the internet, can anyone give me any tips?
Print
import os
from ast import Str
file = open("example.txt", "r")
replacement = ""
data = "02/07/2022"
name = "Alan"
for line in file:
line = line.strip()
changes = line.replace("__/__/____", data)
replacement = replacement + changes + "\n"
file.close()
fout = open("final.txt", "w")
fout.write(replacement)
fout.close()

You don't need to do this a line a time. You can replace that entire program with this:
data = "02/07/2022"
name = "Alan"
text = open("example.txt", "r").read().replace("__/__/____", data)
open("final.txt", "w").write(text)

How to add for loop in python?

I'm creating new files from originally existing ones in the mdp folder by changing a couple of lines in those files using python. I need to do this for 1000 files. Can anyone suggest a for loop which reads all files and changes them and creates new in one go?
This way I have to change the the number followed by 'md_' in the path and it's tedious because there are a 1000 files here.
I tried using str() but there was a 'could not read file error'
fin = open("/home/abc/xyz/mdp/md_1.mdp", "rt")
fout = open("/home/abc/xyz/middle/md_1.mdp", "wt")
for line in fin:
fout.write(line.replace('integrator = md', 'integrator
= md-vv'))
fin = open("/home/abc/xyz/middle/md_1.mdp", "rt")
fout = open("/home/abc/xyz/mdb/md_1.mdp", "wt")
for line in fin:
fout.write(line.replace('dt = 0.001', 'dt
= -0.001'))
fin.close()
fout.close()

os.listdir(path) is your friend:
import os
sourcedir = "/home/abc/xyz/mdp"
destdir = "/home/abc/xyz/middle"
for filename in os.listdir(sourcedir):
if not filename.endswith(".mdp"):
continue
source = os.path.join(sourcedir, filename)
dest = os.path.join(destdir, filename)
# with open(xxx) as varname makes sure the file(s)
# will be closed whatever happens in the 'with' block
# NB text mode is the default, and so is read mode
with open(source) as fin, open(dest, "w") as fout:
# python files are iterable... avoids reading
# the whole file in memory at once
for line in fin:
# will only work for those exact strings,
# you may want to use regexps if number of
# whitespaces vary etc
line = line.replace("dt = 0.001", "dt = -0.001")
line = line.replace(
'integrator = md',
'integrator = md-vv'
)
fout.write(line)

Assuming you want to edit all files that are located in the mdp folder you could do something like this.
import os
dir = "/home/abc/xyz/mdp/"
for filename in os.listdir(dir):
with open(dir + filename, "r+") as file:
text = file.read()
text = text.replace("dt = 0.001", "dt = -0.001")
file.seek(0)
file.write(text)
file.truncate()
This will go through every file and change it using str.replace().
If there are other files in the mdp folder that you do not want to edit, you could use and if-statement to check for the correct file name. Add something like this to encase the with open statement.
if filename.startswith("md_")

How to loop through each file in a folder, do some action to the file and save output to a file in another folder Python

I have a folder with multiple files like so:
1980
1981
1982
In each of these files is some text. I want to loop through each of these files and do some operation to each file then save the edited file to another folder and move onto the next file and so on. The result would be that I have the original folder and then another folder with the edited version of each file in it like so:
1980_filtered
1981_filtered
1982_filtered
Is it possible to do this?
Currently I have some code that loops through the files in a folder, does some filtering to each file and then saves all the edits of each file into one massive file. Here is my code:
import os
input_location = 'C:/Users/User/Desktop/mini_mouse'
output_location = 'C:/Users/User/Desktop/filter_mini_mouse/mouse'
for root, dir, files in os.walk(input_location):
for file in files:
os.chdir(input_location)
with open(file, 'r') as f, open('NLTK-stop-word-list', 'r') as f2:
mouse_file = f.read().split() # reads file and splits it into a list
stopwords = f2.read().split()
x = (' '.join(i for i in mouse_file if i.lower() not in (x.lower() for x in stopwords)))
with open(output_location, 'a') as output_file:
output_file.write(x)
Any help would be greatly appreciated!

You need to specify what each new file is called. To do so, Python has some good string formatting methods. Fortunately, your new desired file names are easy to do in a loop
import os
input_location = 'C:/Users/User/Desktop/mini_mouse'
output_location = 'C:/Users/User/Desktop/filter_mini_mouse/mouse'
for root, dir, files in os.walk(input_location):
for file in files:
new_file = "{}_filtered.txt".format(file)
os.chdir(input_location)
with open(file, 'r') as f, open('NLTK-stop-word-list', 'r') as f2:
mouse_file = f.read().split()
stopwords = f2.read().split()
x = (' '.join(i for i in mouse_file if i.lower() not in (x.lower() for x in stopwords)))
with open(output_location+'/'+new_file, 'w') as output_file: # Changed 'append' to 'write'
output_file.write(x)
If you're in Python 3.7, you can do
new_file = f"{file}_filtered.txt"
and
with open(f"{output_location}/{new_file}", 'w') as output_file:
output_file.write(x)

First of all you should start by opening the NLTK-stop-word-list only once, so I moved it outside of your loops. Second, os.chdir() is redundant, you can use os.path.join() to get your current file path (and to construct your new file path):
import os
input_location = 'C:/Users/User/Desktop/mini_mouse'
output_location = 'C:/Users/User/Desktop/filter_mini_mouse/'
stop_words_path = 'C:/Users/User/Desktop/NLTK-stop-word-list.txt'
with open(stop_words_path, 'r') as stop_words:
for root, dirs, files in os.walk(input_location):
for name in files:
file_path = os.path.join(root, name)
with open(file_path, 'r') as f:
mouse_file = f.read().split() # reads file and splits it into a list
stopwords = stop_words.read().split()
x = (' '.join(i for i in mouse_file if i.lower() not in (x.lower() for x in stopwords)))
new_file_path = os.path.join(output_location, name) + '_filtered'
with open(new_file_path, 'a') as output_file:
output_file.write(x)
P.S: I took the liberty to change some of your variable names as they were part of python's built in words ('file' and 'dir'). If you'll run __builtins__.__dict__.keys() you'll see them there.

replace line if found or append - python

I have text that is key-value pairs separated by '='. I would like to replace the line if the key matches. if not, i would like to append it at the bottom. I've tried several ways, including:
def split_command_key_and_value(command):
if '=' in command:
command2 = command.split('=')
return command2
def test(command, path):
command2 = split_command_key_and_value(command)
pattern = command2[0]
myfile = open(path,'r') # open file handle for read
# use r'', you don't need to replace '\' with '/'
result = open(path, 'w') # open file handle for write
for line in myfile:
line = line.strip() # it's always a good behave to strip what you read from files
if pattern in line:
line = command # if match, replace line
result.write(line) # write every line
myfile.close() # don't forget to close file handle
result.close()
I know the above is just to replace text, but it deletes the text in the file, and I can't see why. Could someone point me in the right direction?
Thanks
Update:
I'm almost there, but some of my lines have similar keys, so mutiple lines are matching when only 1 should. I've tried to incorporate a regex boundary in my loop with no luck. My code is below. Does anyone have a suggestion?
There is some text in the file that isn't key-value, so I would like to skip that.
def modify(self, name, value):
comb = name + ' ' + '=' + ' ' + value + '\n'
with open('/file/', 'w') as tmpstream:
with open('/file/', 'r') as stream:
for line in stream:
if setting_name in line:
tmpstream.write(comb)
else:
tmpstream.write(line)
I think I got it. See code below.
def modify(self, name, value):
comb = name + ' ' + '=' + ' ' + value + '\n'
mylist = []
with open('/file/', 'w') as tmpstream:
with open('/file/', 'r') as stream:
for line in stream:
a = line.split()
b = re.compile('\\b'+name+'\\b')
if len(a) > 0:
if b.search(a[0]):
tmpstream.write(comb)
else:
tmpstream.write(line)
I spoke too soon. It stops at the key-value I provide. So, it only writes one line, and doesn't write the lines that don't match.
def modify(name, value):
comb = name + ' ' + '=' + ' ' + value + '\n'
mylist = []
with open('/file1', 'w') as tmpstream:
with open('/file2', 'r') as stream:
for line in stream:
a = line.split()
b = re.compile('\\b'+name+'\\b')
if len(a) > 0:
if b.search(a[0]):
tmpstream.write(comb)
else:
tmpstream.write(line)
Can anyone see the issue?

Because when you open file for writing
result = open(path, 'w') # open file handle for write
you just erase it content. Try to write in different file and after all work done replace old file with new one. Or read all data into memory and then process it and write to file.
with open(path) as f:
data = f.read()
with open(path, 'w') as f:
for l in data:
# make job here

first of all you are reading an writing the same file ...
you could first read it all and the write line by line
with open(path,'r') as f:
myfile = f.read() # read everything in the variable "myfile"
result = open(path, 'w') # open file handle for write
for line in myfile.splitlines(): # process the original file content 1 line at a time
# as before

I strongly recommend reading python's documentation on how to read and write files.
If you open an existing file in write-mode open(path, 'w'), its content will be erased:
mode can be (...) 'w' for only writing (an existing file with the same name will be erased)
To replace a line in python you can have a look at this: Search and replace a line in a file in Python
Here is one the solutions provided there adapted to your context (tested for python3):
from tempfile import mkstemp
from shutil import move
from os import close
def test(filepath, command):
# Split command into key/value
key, _ = command.split('=')
matched_key = False
# Create a temporary file
fh, tmp_absolute_path = mkstemp()
with open(tmp_absolute_path, 'w') as tmp_stream:
with open(filepath, 'r') as stream:
for line in stream:
if key in line:
matched_key = True
tmp_stream.write(command + '\n')
else:
tmp_stream.write(line)
if not matched_key:
tmp_stream.write(command + '\n')
close(fh)
move(tmp_absolute_path, filepath)
Note that with the code above every line that matches key (key=blob or blob=key) will be replaced.

I m searching for a specific string in multiple ".txt" files using python

I'm trying to search strings like "a.aiq" in multiple .txt files and I want those ".aiq" results to be printed
So far I have written below code. It gives no error but doesn't give me desired result.
import glob
import re
import os
src = "C:\Python26\sample"
file_array = glob.glob(os.path.join(src,"*.txt"))
fi = open("aiq_hits.txt","w")
for input_file in file_array:
fo = open(input_file,"r")
line= fo.readline()
for line in fo:
line=line.strip()
x= re.findall('\S *.aiq\S*',line)
line= fo.readline()
for item in x:
fi.write("%s\n" % item)
fo.close()
fi.close()

str = fo.readline()
while str:
...
str = fo.readline()
should be replaced by:
for str in fo:
The first question is:
Is file_array correct?
Use for example
for input_file in file_array:
print input_file #add parenthesis in python 3