How to save a changed item to an external file? (Python 3) - python

I'm fairly new to python, but I'm making a script and I want one of the functions to update a variable from another file. It works, but when I exit the script and reload it, the changes aren't there anymore. For example (this isn't my script):
#File: changeFile.txt
number = 0
#File: changerFile.py
def changeNumber():
number += 1
If I retrieve number during that session, it will return 1, but if I exit out and go back in again and retrieve number without calling changeNumber, it returns 0.
How can I get the script to actually save the number edited in changeNumber to changeFile.txt? As I said, I'm fairly new to python, but I've looked just about everywhere on the Internet and couldn't really find an answer that worked.
EDIT: Sorry, I forgot to include that in the actual script, there are other values.
So I want to change number and have it save without deleting the other 10 values stored in that file.

Assuming, as you show, that changeFile.txt has no other content whatever, then just change the function to:
def changeNumber():
global number # will not possibly work w/o this, the way you posted!
number += 1
with open('changeFile.txt', 'w') as f:
f.write('number = {}\n'.format(number))
ADDED: the OP edited the Q to mention (originally omitted!-) the crucial fact that changefile.txt has other lines that need to be preserved as well as the one that needs to be changed.
That, of course, changes everything -- but, Python can cope!-)
Just add import fileinput at the start of this module, and change the last two lines of the above snippet (starting with with) to:
for line in fileinput.input(['changefile.txt'], inplace=True):
if line.startswith('number ');
line = 'number = {}\n'.format(number)'
print line,
This is the Python 2 solution (the OP didn't bother to tell us if using Py2 or Py3, a crucial bit of info -- hey, who cares about making it easy rather than very hard for willing volunteers to help you, right?!-). If Python 3, change the last statement from print line, to
print(line, end='')
to get exactly the same desired effect.

Related

creating multiple iteration of the same code

beginer question:
I often have to repeat the same line of code 10 times for 10 different variables (i read you can't or should not create variable dynamically)
I thought to help me once i written it once I could iterate with a find replace (I am currently doing it in word)
I wrote this but get tons of error when i input code like if console trying to execute the code. what am i missing? is it because i paste it i the console does it need to be imported from a ext file ?
LineOfCode = input("Enter the code you want to iterate the iteration variable need be 8")
for i in range(10):
LineOfCode.replace("8",str(i))
print(LineOfCode)
Your code is almost correct:
String.replace() returns a new string with the changes, doesn't change the existing string. So the code should be like:
LineOfCode = input("Enter the code you want to iterate the iteration variable need be 8")
for i in range(10):
var = LineOfCode.replace("8", str(i))
print(var)
The question isn't clear enough, so if this isn't what you wanted, edit the question.
Besides this, you can use Visual Code as an IDE, it'll make things much, much easier than Word.
About the errors, I think you might be trying to run the code directly in console. Instead of typing only the file name, type python file.py, assuming the file name is file. The file must be a python file (ending with .py), also it shouldn't be saved as a word file. It must be plain text.
If you want to run the same code on multiple variables, you can create the code as a string, and then use the builtin exec to execute it. Example:
a = 1
b = 2
c = 3
variables = ["a", "b", "c"]
for var in variables:
exec("print(" + var + ")") # print the variable before modifying
exec(var + " *= 2") # multiply the current variable by 2
exec("print(" + var + ")") # print the variable after modifying
If this is not what you need, your question was not clear enough and i misunderstood it, you just have to provide more information on what excatly you need by adding a comment under your question, in which you first type #Programmer and then your text.

Python function not working with seemingly correct string path

I have the following code (it changes the string/filepath, replacing the numbers at the end of the filename + the file extension, and replaces that with "#.exr")
I was doing it this way because the name can be typed in all kinds of ways, for example:
r_frame.003.exr (but also)
r_12_frame.03.exr
etc.
import pyseq
import re
#create render sequence list
selected_file = 'H:/test/r_frame1.exr'
without_extention = selected_file.replace(".exr", "")
my_regex_pattern = r"\d+\b"
sequence_name_with_replaced_number = re.sub(my_regex_pattern, "#.exr" ,without_extention)
mijn_sequences = fileseq.findSequencesOnDisk(sequence_name_with_replaced_number)
If I print the "sequence_name_with_replaced_number" value, this results in the console in:
'H:/test/r_frame#.exr'
When I use that variable inside that function like this:
mijn_sequences = fileseq.findSequencesOnDisk(sequence_name_with_replaced_number)
Then it does not work.
But when I manually replace that last line into:
mijn_sequences = fileseq.findSequencesOnDisk('H:/test/r_frame#.exr')
Then it works fine. (it's the seems like same value/string)
But this is not an viable option, the whole point of the code if to have the computer do this for thousands of frames.
Anybody any idea what might be the cause of this?
After this I will do simple for loop going trough al the files in that sequence. The reason I'm doing this workflow is to delete the numbers before the .exr file extensions and replace them with # signs. (but ognoring all the bumbers that are not at the end of the filename, hence that regex above. Again, the "sequence_name_with_replaced_number" variable seems ok in the console. It spits out: 'H:/test/r_frame#.exr' (that's what I need it to be)
I fixed it. the problem as stated was correct, every time I did a cut and past from the variable value in the console and treated it as manual input it worked.
Then I did a len() of both values, and there was a difference by 2! What happend? The console added the ''
But in the generated variable it had those baked in as extra letters. i fixed it by adding cleaned_sequence = sequence_name_with_replaced_number[1:-1] so 'H:/test/r_frame1.exr' (as the console showed me) was not the same as 'H:/test/r_frame1.exr' (what I inserted manually, because I added these marks, in the console there are showed automatically)

Pulling Vars from lists and applying them to a function

I'm working on a project in my work using purely Python 3:
If I take my scanner, (Because I work in inventory) and anything I scan goes into a text doc, and I scan the location "117" , and then I scan any device in any other location, (the proceeding lines in the text doc "100203") and I run the script and it plugs in '117' in the search on our database and changes each of the devices (whether they were assigned to that location or not) into that location, (Validating those devices are in location '117')
My main question is the 3rd objective down from the Objectives list below that doesn't have "Done" after it.
Objective:
Pull strings from a text document, convert it into a dictionary. = (Text_Dictionary) **Done**
Assign the first var in the dictionary to a separate var. = (First_Line) **Done**
All proceeding var's greater then the first var in the dictionary should be passed into a function individually. = (Proceeding_Lines)
Side note: The code should loop in a fashion that should (.pop) the var from the dictionary/list, But I'm open for other alternatives. (Not mandatory)
What I already have is:
Project.py:
1 import re
2 import os
3 import time
4 import sys
5
6 with open(r"C:\Users\...\text_dictionary.txt") as f:
7 Text_Dictionary = [line.rstrip('\n') for line in
8 open(r"C:\Users\...\text_dictionary.txt")]
9
10 Text_Dict = (Text_Dictionary)
11 First_Line = (Text_Dictionary[0])
12
13 print("The first line is: ", First_Line)
14
15 end = (len(Text_Dictionary) + 1)
16 i = (len(Text_Dictionary))
17
What I have isn't much on the surface, but I have another "*.py" file fill of code that I am going to copy in for the action that I wish to preform on each of the vars in the Text_Dictionary.txt. Lines 15 - 16 was me messing with what I thought might solve this.
In the imported text document, the var's look very close to this (Same length)(All digits):
Text_Dictionary.txt:
117
23000
53455
23454
34534
...
Note: These values will change for each time the code is ran, meaning someone will type/scan in these lines of digits each time.
Explained concept:
Ideally, I would like to have the first line point towards a direction, and the rest of the digits would follow; however, each (Example: '53455') needs to be ran separately then the next in line and (Example: '117') would be where '53455' goes. You could say the first line is static throughout the code, unless otherwise changed inText_Dictionary.txt. '117'is ran in conjunction with each iteration proceeding it.
Background:
This is for inventory management for my office, I am in no way payed for doing this, but it would make my job a heck-of-a-lot easier. Also, I know basic python to get myself around, but this kinda stumped me. Thank you to whoever answers!
I've no clue what you're asking, but I'm going to take a guess. Before I do so, your code was annoying me:
with open("file.txt") as f:
product_ids = [line.strip() for line in f if not line.isspace()]
There. That's all you need. It protects against blank lines in the file and weird invisible spaces too, this way. I decided to leave the data as strings because it probably represents an inventory ID, and in the future that might be upgraded to "53455-b.42454#62dkMlwee".
I'm going to hazard a guess that you want to run different code depending on the number at the top. If so, you can use a dictionary containing functions. You said that you wanted to run code from another file, so this is another_file.py:
__all__ = ["dispatch_whatever"]
dispatch_whatever = {}
def descriptive_name_for_117(product_id):
pass
dispatch_whatever["117"] = descriptive_name_for_117
And back in main_program.py, which is stored in the same directory:
from another_file import dispatch_whatever
for product_id in product_ids[1:]:
dispatch_whatever[product_ids[0]](product_id)

How to assign a single variable to a specific line in python?

I was not clear enough in my last question, and so I'll explain my question more this time.
I am creating 2 separate programs, where the first one will create a text file with 2 generated numbers, one on line 1 and the second on line 2.
Basically I saved it like this:
In this example I'm not generating numbers, just assigning them quickly.
a = 15
b = 16
saving = open('filename.txt', "w")
saving.write(a+"\n")
saving.write(b+"\n")
saving.close()
Then I opened it on the next one:
opening = open('filename.txt', "w")
a = opening.read()
opening.close()
print(a) #This will print the whole document, but I need each line to be differnet
Now I got the whole file loaded into 'a', but I need it split up, which is something that i have not got a clue on how to do. I don't believe creating a list will help, as I need each number (Variables a and b from program 1) to be different variables in program 2. The reason I need them as 2 separate variables is because I need to divide it by a different number. If I do need to do a list, please say. I tried finding an answer for about an hour in total, though I couldn't find anything.
The reason I can't post the whole program is because I haven't got access to it from here, and no, this is not cheating as we are free to research and ask questions outside the classroom, if someone wonders about that after looking at my previous question.
If you need more info please put it in a comment and I'll respond ASAP.
opening = open('filename.txt') # "w" is not necessary since you're opening it read-only
a = [b.split() for b in opening.readlines()] # create a list of each line and strip the newline "\n" character
print(a[0]) # print first line
print(a[1]) # print second line

Separate functions in python?

I'm not sure if function is the word I am looking for. In fact I don't really know what I'm saying but I have some code and it's not quite doing it what I want to. Basically I want to copy and paste this code I've got and email it to someone. I want them to be able to simply copy and paste it into their Terminal and perform calculations.:
## SCSAC.py
def round(x, base=5):
return int(base * round(float(x)/base))
option = 'yes'
while (option == 'yes'):
x=float(raw_input('How many accumulated orders do you have from retailers: '));
y=float(raw_input('How many units are in the inventory: '));
z=float(raw_input('How many accumulated orders have you placed: '));
print 'Place an order of %s units' % round(((x / 25 + y / 10 + z / 25) + 115));
print ;
option=raw_input("Do you wish to calculate another order? (Enter 'yes' to continue or any other key to quit):: ");
print
Whenever I type this code in line for line, it works perfectly. That's because there are basically 3 seperate things happening here.
I define "round" which rounds a value to the nearest 5.
I define an option to loop the program upon completion
I define the actual program, and in that I round the answer and conclude with the option to loop. You may notice 2 print's that don't print anything, but they are only there to have blank lines.
When I copy and paste it, I get a syntax error.
I am not a programmer and I have just been playing with this all day. I just want to know how I can edit this code so it is copy/paste-able and will run the way it is supposed to.
Try using IPython instead of the regular Python interpret at the shell. With IPython, you can type %cpaste, and then paste a whole chunk of code, which it will execute for you step by step, saving the intermediate variables into working memory.
If you insist on pasting it in the regular interpreter, then do it line by line, and take special care for the indentations. The indentations are usually where paste syntax errors come from.
Even better, use Emacs. Then you can just save the pasted code into a file, like test.py, type M-x shell, and then python test.py to quickly run it. Or, if you saved it to a file like test.py then in IPython you can also type %run "test.py" and it will run the code and again store intermediate variables into working memory.
If you're copy/pasting this after making changes more than once or twice, just save it to a file and run it like a script.
You can save the code in a file, and run it using Python.
You can add #!/usr/bin/env python to the beginning of the file, so it can run on *nix systems (if you have execute permission).
Or, you can do python SCSAC.py and run your code. This works on all systems (AFAIK). You can email the file to your person, and she can run it using Python. This seems to be the easiest way to do it.

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