I have a python program that just needs to save one line of text (a path to a specific folder on the computer).
I've got it working to store it in a text file and read from it; however, I'd much prefer a solution where the python file is the only one.
And so, I ask: is there any way to save text in a python program even after its closed, without any new files being created?
EDIT: I'm using py2exe to make the program an .exe file afterwards: maybe the file could be stored in there, and so it's as though there is no text file?
You can save the file name in the Python script and modify it in the script itself, if you like. For example:
import re,sys
savefile = "widget.txt"
x = input("Save file name?:")
lines = list(open(sys.argv[0]))
out = open(sys.argv[0],"w")
for line in lines:
if re.match("^savefile",line):
line = 'savefile = "' + x + '"\n'
out.write(line)
This script reads itself into a list then opens itself again for writing and amends the line in which savefile is set. Each time the script is run, the change to the value of savefile will be persistent.
I wouldn't necessarily recommend this sort of self-modifying code as good practice, but I think this may be what you're looking for.
Seems like what you want to do would better be solved using the Windows Registry - I am assuming that since you mentioned you'll be creating an exe from your script.
This following snippet tries to read a string from the registry and if it doesn't find it (such as when the program is started for the first time) it will create this string. No files, no mess... except that there will be a registry entry lying around. If you remove the software from the computer, you should also remove the key from the registry. Also be sure to change the MyCompany and MyProgram and My String designators to something more meaningful.
See the Python _winreg API for details.
import _winreg as wr
key_location = r'Software\MyCompany\MyProgram'
try:
key = wr.OpenKey(wr.HKEY_CURRENT_USER, key_location, 0, wr.KEY_ALL_ACCESS)
value = wr.QueryValueEx(key, 'My String')
print('Found value:', value)
except:
print('Creating value.')
key = wr.CreateKey(wr.HKEY_CURRENT_USER, key_location)
wr.SetValueEx(key, 'My String', 0, wr.REG_SZ, 'This is what I want to save!')
wr.CloseKey(key)
Note that the _winreg module is called winreg in Python 3.
Why don't you just put it at the beginning of the code. E.g. start your code:
import ... #import statements should always go first
path = 'what you want to save'
And now you have path saved as a string
Related
I have a simple JSON file that I was supposed to use as a configuration file, it contains the default directories for whoever is running the script using their MacBooks:
{
"main_sheet_path": "/Users/jammer/Documents/Studios/CAT/000-WeeklyReports/2020/",
"reference_sheet_path": "/Users/jammer/Documents/DownloadedFiles/"
}
I read the JSON file and obtain the values using this code:
with open('reportconfig.json','r') as j:
config_data = json.load(j)
main_sheet_path = str(config_data.get('main_sheet_path'))
reference_sheet_path = str(config_data.get('reference_sheet_path'))
I use the path to check for a source file's existence before doing anything with it:
source_file = 'source.xlsx'
source_file = main_sheet_path + filename
if not os.path.isfile(source_file) :
print ('ERROR: Source file \'' + source_file + '\' NOT FOUND!')
return
Note that the filename is inputted as a parameter when the script is run (there are multiple files, the script has to know which one to target).
The file is there for sure but the script never seems to "see" it so I get that "ERROR" that I printed in the above code. Why do I think there are invisible characters? Because when I copy and paste from what was printed in the "error" notice above into the terminal, the last few characters of the file name always gets substituted by some invisible characters and hitting backspace erases characters where the cursor isn't supposed to be.
How do I know for sure that the file is there and that my problem is with reading the JSON file and not in the Directory names or anywhere else in the code? Because I finally gave up on using a JSON config file and went with a configuration file like this instead:
#!/usr/local/bin/python3.7
# -*- coding: utf-8 -*-
file_paths = { "main_sheet_path": "/Users/jammer/Documents/Studios/CAT/000-WeeklyReports/2020/",
"reference_sheet_path": "/Users/jammer/Documents/DownloadedFiles/"
}
I then just import the file and obtain the values like this:
import reportconfig as cfg
main_sheet_path = cfg.file_paths['main_sheet_path']
reference_sheet_path = cfg.file_paths['reference_sheet_path']
...
This workaround works perfectly — I don't get the "error" that the file isn't there when it is and the rest of the script is executed as expected. When the file isn't there, I get the proper "error" I expect and copying-and-pasting the full path and filename from the "error message" gives me the complete file name and hitting the backspace erases the right characters (no funny behavior, no invisible characters).
But could anyone please tell me how read the JSON file properly without getting those pesky invisible characters? I've spent hours trying to figure it out including searching seemingly related questions in stackoverflow but couldn't find the answer. TIA!
I think there is just a typo error in this code:
source_file = 'source.xlsx'
source_file = main_sheet_path + filename
Maybe filename is set to some other file which is not present hence it is giving you error.
Try to set filename='source.xlsx'
Maybe it will help
i wanted to make a python file that makes a copy of itself, then executes it and closes itself, then the copy makes another copy of itself and so on...
i am not asking for people to write my code and this could be taken as just a fun challenge, but i want to learn more about this stuff and help is appreciated.
i have already played around with it but can't wrap my mind around it,
I've already tried making a py file and just pasting a copy of the file itself in it two different ways i could think of but it would just go on forever.
#i use this piece of code to easily execute the py file using os
os.startfile("file.py")
#and to make new py file i just use open()
file = open("file.py","w")
file.write("""hello world
you can use 3 quote marks to write over multiple lines""")
i expect that when you run the program it makes a copy of itself, runs it, and closes itself, and the newly ran program loops over.
what actually happenes is that either I'm writing code forever or,
when i embed the code it pastes in the copy of itself into what it copies to the copy file,
it rightfully says it doesn't know what that code is because it's being written.
it's all really confusing and this is difficult to explain and I'm sorry
it's midnight atm and I'm tired.
I don't have enough rep to reply to #Prune:
os.startfile(file) only works on Windows, and is replaced by subprocess.call
shutil.copy2(src, dst) works on both Windows and Linux.
Try this solution as well:
import shutil
import subprocess
old_file = __file__
new_file = generate_unique_file_name()
shutil.copy2(old_file, new_file) # works for both Windows and Linux
subprocess.call('python {}'.format(new_file), shell=True)
You're close; you have things in the wrong order. Create the new file, then execute it.
import os
old_file = __file__
new_file = generate_unique_file_name()
os.system('cp ' + old_file + ' ' + new_file) #UNIX syntax; for Windows, use "copy"
os.startfile(new_file)
You'll have to choose & code your preferred method for creating a unique file name. You might want to use a time-stamp as part of the name.
You might also want to delete this file before you exit; otherwise, you'll eventually fill your disk with these files.
I'm making a troubleshooting program in which I need to take a python program which is stored in a text file, but I can't use the 'import' module. To clarify this, there would be a python program stored as a '.txt' file, and in the main program I would take this text file and be able to use it as a subprogram. I've tried doing this, but I have had no clue of how to go about it, especially since I do not have much experience of Python.
Below is roughly the program. I don't know how to format it either, but here goes:
phonechoice = input("What type of phone do you have?")
if 'iphone' in phonechoice:
#here I would load a text file which contains the program for the iphone
#which asks them what problem they have with their phone and gives a solution
I'm wondering how I can do this. I thought how I could do this and maybe I could 'copy and paste' the program, line by line, into a definition, which I could then use. Would this work, and if it doesn't then in what other way could I do it?
Rename the text file to a python file, i.e. change the extension to ".py". This does not change the fact that it is a text file, just like renaming a picture.jpg file to picture.txt does not change the fact that it's an image file.
If you have some wacky requirement to import a module saved in file with a .txt extension, you can not use an import statement. But it is still possible to import like this:
import imp
my_module = imp.load_source('my_module', 'example.txt')
I am a bit reluctant to answer a "homework" type question, but I will give you some pointers on what you need to do. If I have a text file with this in it:
def main():
print("Hello")
main()
I could execute the code with the exec function like this:
with open("filename.txt") as file: #filename should be the name of the file
data = file.read()
exec(data) #this executes the code
The output would be as expected:
Hello
Hopefully this will shed some light on your problem!
In IronPython 2.6*, I'm trying to build a function that "corrects" a string; I have two arguments, FILE and EXTN. The idea is for them to be concatenated as necessary later in the program, but you know some people don't read instructions and you're bound to have someone enter "FILE.*" as their FILE, which would mess everything up.
I'm looking for a way to take FILE, have my function detect and strip .* (any extension of any length) from FILE if .* exists; It doesn't need to be in the string, and the user will be entering the same extension into EXTN**, so it needs not be prepared, merely consistently stripped.
My current method has me passing FILE and EXTN separately, but it's not inconceivable to redo things to take FILE.EXTN and break that into FILE and EXTN if need be; I don't want to if I don't have to, though, as my program is built around the former system.
*A note regarding IronPython 2.6; I'm trying to avoid IronPython-specific codes and use as simple of ones as possible, for UNIX-WIN cross-compatibility's sake. So far, everything I've done works in Python 2.7 IDE's, but obviously will not work in Python 3.x
**A note regaring EXTN; I want users to enter the proper extension into EXTN too, but as we know, we can't be sure of this and so the method for stripping .i from FILE must not automatically include EXTN as part of it.
Here is a snippet of code that may help as a reference for what I have so far. The FILE and EXTN variables have been added, and in practice, are pulled in through a middle-man program from an XML file into the script at run-time.
FILE = "test"
PATH = "C:\\"
EXTN = ".txt"
def CheckCorrect_FILE(srcFile): #Check-corrects FILE
#Meh, I got nothin'...
def CheckCorrect_PATH(srcPath): #Check-corrects PATH
if srcPath.endswith('\\') == False:
srcPath = srcPath + "\\"
else:
srcPath = srcPath
return srcPath
You can do this using os.path.splitext. The following will always remove an extension if one exists (and do nothing if it doesn't):
import os
FILE = os.path.splitext(FILE)[0]
I'm trying to automate downloading of some text files from a z/os PDS, using Python and ftplib.
Since the host files are EBCDIC, I can't simply use FTP.retrbinary().
FTP.retrlines(), when used with open(file,w).writelines as its callback, doesn't, of course, provide EOLs.
So, for starters, I've come up with this piece of code which "looks OK to me", but as I'm a relative Python noob, can anyone suggest a better approach? Obviously, to keep this question simple, this isn't the final, bells-and-whistles thing.
Many thanks.
#!python.exe
from ftplib import FTP
class xfile (file):
def writelineswitheol(self, sequence):
for s in sequence:
self.write(s+"\r\n")
sess = FTP("zos.server.to.be", "myid", "mypassword")
sess.sendcmd("site sbd=(IBM-1047,ISO8859-1)")
sess.cwd("'FOO.BAR.PDS'")
a = sess.nlst("RTB*")
for i in a:
sess.retrlines("RETR "+i, xfile(i, 'w').writelineswitheol)
sess.quit()
Update: Python 3.0, platform is MingW under Windows XP.
z/os PDSs have a fixed record structure, rather than relying on line endings as record separators. However, the z/os FTP server, when transmitting in text mode, provides the record endings, which retrlines() strips off.
Closing update:
Here's my revised solution, which will be the basis for ongoing development (removing built-in passwords, for example):
import ftplib
import os
from sys import exc_info
sess = ftplib.FTP("undisclosed.server.com", "userid", "password")
sess.sendcmd("site sbd=(IBM-1047,ISO8859-1)")
for dir in ["ASM", "ASML", "ASMM", "C", "CPP", "DLLA", "DLLC", "DLMC", "GEN", "HDR", "MAC"]:
sess.cwd("'ZLTALM.PREP.%s'" % dir)
try:
filelist = sess.nlst()
except ftplib.error_perm as x:
if (x.args[0][:3] != '550'):
raise
else:
try:
os.mkdir(dir)
except:
continue
for hostfile in filelist:
lines = []
sess.retrlines("RETR "+hostfile, lines.append)
pcfile = open("%s/%s"% (dir,hostfile), 'w')
for line in lines:
pcfile.write(line+"\n")
pcfile.close()
print ("Done: " + dir)
sess.quit()
My thanks to both John and Vinay
Just came across this question as I was trying to figure out how to recursively download datasets from z/OS. I've been using a simple python script for years now to download ebcdic files from the mainframe. It effectively just does this:
def writeline(line):
file.write(line + "\n")
file = open(filename, "w")
ftp.retrlines("retr " + filename, writeline)
You should be able to download the file as a binary (using retrbinary) and use the codecs module to convert from EBCDIC to whatever output encoding you want. You should know the specific EBCDIC code page being used on the z/OS system (e.g. cp500). If the files are small, you could even do something like (for a conversion to UTF-8):
file = open(ebcdic_filename, "rb")
data = file.read()
converted = data.decode("cp500").encode("utf8")
file = open(utf8_filename, "wb")
file.write(converted)
file.close()
Update: If you need to use retrlines to get the lines and your lines are coming back in the correct encoding, your approach will not work, because the callback is called once for each line. So in the callback, sequence will be the line, and your for loop will write individual characters in the line to the output, each on its own line. So you probably want to do self.write(sequence + "\r\n") rather than the for loop. It still doesn' feel especially right to subclass file just to add this utility method, though - it probably needs to be in a different class in your bells-and-whistles version.
Your writelineswitheol method appends '\r\n' instead of '\n' and then writes the result to a file opened in text mode. The effect, no matter what platform you are running on, will be an unwanted '\r'. Just append '\n' and you will get the appropriate line ending.
Proper error handling should not be relegated to a "bells and whistles" version. You should set up your callback so that your file open() is in a try/except and retains a reference to the output file handle, your write call is in a try/except, and you have a callback_obj.close() method which you use when retrlines() returns to explicitly file_handle.close() (in a try/except) -- that way you get explict error handling e.g. messages "can't (open|write to|close) file X because Y" AND you save having to think about when your files are going to be implicitly closed and whether you risk running out of file handles.
Python 3.x ftplib.FTP.retrlines() should give you str objects which are in effect Unicode strings, and you will need to encode them before you write them -- unless the default encoding is latin1 which would be rather unusual for a Windows box. You should have test files with (1) all possible 256 bytes (2) all bytes that are valid in the expected EBCDIC codepage.
[a few "sanitation" remarks]
You should consider upgrading your Python from 3.0 (a "proof of concept" release) to 3.1.
To facilitate better understanding of your code, use "i" as an identifier only as a sequence index and only if you irredeemably acquired the habit from FORTRAN 3 or more decades ago :-)
Two of the problems discovered so far (appending line terminator to each character, wrong line terminator) would have shown up the first time you tested it.
Use retrlines of ftplib to download file from z/os, each line has no '\n'.
It's different from windows ftp command 'get xxx'.
We can rewrite the function 'retrlines' to 'retrlines_zos' in ftplib.py.
Just copy the whole code of retrlines, and chane the 'callback' line to:
...
callback(line + "\n")
...
I tested and it worked.
you want a lambda function and a callback. Like so:
def writeLineCallback(line, file):
file.write(line + "\n")
ftpcommand = "RETR {}{}{}".format("'",zOsFile,"'")
filename = "newfilename"
with open( filename, 'w' ) as file :
callback_lambda = lambda x: writeLineCallback(x,file)
ftp.retrlines(ftpcommand, callback_lambda)
This will download file 'zOsFile' and write it to 'newfilename'