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Extract text from a config file [duplicate]

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Parse key value pairs in a text file
(7 answers)
Closed 1 year ago.
I'm using a config file to inform my Python script of a few key-values, for use in authenticating the user against a website.
I have three variables: the URL, the user name, and the API token.
I've created a config file with each key on a different line, so:
url:<url string>
auth_user:<user name>
auth_token:<API token>
I want to be able to extract the text after the key words into variables, also stripping any "\n" that exist at the end of the line. Currently I'm doing this, and it works but seems clumsy:
with open(argv[1], mode='r') as config_file:
lines = config_file.readlines()
for line in lines:
url_match = match('jira_url:', line)
if url_match:
jira_url = line[9:].split("\n")[0]
user_match = match('auth_user:', line)
if user_match:
auth_user = line[10:].split("\n")[0]
token_match = match('auth_token', line)
if token_match:
auth_token = line[11:].split("\n")[0]
Can anybody suggest a more elegant solution? Specifically it's the ... = line[10:].split("\n")[0] lines that seem clunky to me.
I'm also slightly confused why I can't reuse my match object within the for loop, and have to create new match objects for each config item.

you could use a .yml file and read values with yaml.load() function:
import yaml
with open('settings.yml') as file:
settings = yaml.load(file, Loader=yaml.FullLoader)
now you can access elements like settings["url"] and so on

If the format is always <tag>:<value> you can easily parse it by splitting the line at the colon and filling up a custom dictionary:
config_file = open(filename,"r")
lines = config_file.readlines()
config_file.close()
settings = dict()
for l in lines:
elements = l[:-1].split(':')
settings[elements[0]] = ':'.join(elements[1:])
So, you get a dictionary that has the tags as keys and the values as values. You can then just refer to these dictionary entries in your pogram.
(e.g.: if you need the auth_token, just call settings["auth_token"]

if you can add 1 line for config file, configparser is good choice
https://docs.python.org/3/library/configparser.html
[1] config file : 1.cfg
[DEFAULT] # configparser's config file need section name
url:<url string>
auth_user:<user name>
auth_token:<API token>
[2] python scripts
import configparser
config = configparser.ConfigParser()
config.read('1.cfg')
print(config.get('DEFAULT','url'))
print(config.get('DEFAULT','auth_user'))
print(config.get('DEFAULT','auth_token'))
[3] output
<url string>
<user name>
<API token>
also configparser's methods is useful
whey you can't guarantee config file is always complete

You have a couple of great answers already, but I wanted to step back and provide some guidance on how you might approach these problems in the future. Getting quick answers sometimes prevents you from understanding how those people knew about the answers in the first place.
When you zoom out, the first thing that strikes me is that your task is to provide config, using a file, to your program. Software has the remarkable property of solve-once, use-anywhere. Config files have been a problem worth solving for at least 40 years, so you can bet your bottom dollar you don't need to solve this yourself. And already-solved means someone has already figured out all the little off-by-one and edge-case dramas like stripping line endings and dealing with expected input. The challenge of course, is knowing what solution already exists. If you haven't spent 40 years peeling back the covers of computers to see how they tick, it's difficult to "just know". So you might have a poke around on Google for "config file format" or something.
That would lead you to one of the most prevalent config file systems on the planet - the INI file. Just as useful now as it was 30 years ago, and as a bonus, looks not too dissimilar to your example config file. Then you might search for "read INI file in Python" or something, and come across configparser and you're basically done.
Or you might see that sometime in the last 30 years, YAML became the more trendy option, and wouldn't you know it, PyYAML will do most of the work for you.
But none of this gets you any better at using Python to extract from text files in general. So zooming in a bit, you want to know how to extract parts of lines in a text file. Again, this problem is an age-old problem, and if you were to learn about this problem (rather than just be handed the solution), you would learn that this is called parsing and often involves tokenisation. If you do some research on, say "parsing a text file in python" for example, you would learn about the general techniques that work regardless of the language, such as looping over lines and splitting each one in turn.
Zooming in one more step closer, you're looking to strip the new line off the end of the string so it doesn't get included in your value. Once again, this ain't a new problem, and with the right keywords you could dig up the well-trodden solutions. This is often called "chomping" or "stripping", and with some careful search terms, you'd find rstrip() and friends, and not have to do awkward things like splitting on the '\n' character.
Your final question is about re-using the match object. This is much harder to research. But again, the "solution" wont necessarily show you where you went wrong. What you need to keep in mind is that the statements in the for loop are sequential. To think them through you should literally execute them in your mind, one after one, and imagine what's happening. Each time you call match, it either returns None or a Match object. You never use the object, except to check for truthiness in the if statement. And next time you call match, you do so with different arguments so you get a new Match object (or None). Therefore, you don't need to keep the object around at all. You can simply do:
if match('jira_url:', line):
jira_url = line[9:].split("\n")[0]
if match('auth_user:', line):
auth_user = line[10:].split("\n")[0]
and so on. Not only that, if the first if triggered then you don't need to bother calling match again - it will certainly not trigger any of other matches for the same line. So you could do:
if match('jira_url:', line):
jira_url = line[9:].rstrip()
elif match('auth_user:', line):
auth_user = line[10:].rstrip()
and so on.
But then you can start to think - why bother doing all these matches on the colon, only to then manually split the string at the colon afterwards? You could just do:
tokens = line.rstrip().split(':')
if token[0] == 'jira_url':
jira_url = token[1]
elif token[0] == 'auth_user':
auth_user = token[1]
If you keep making these improvements (and there's lots more to make!), eventually you'll end up re-writing configparse, but at least you'll have learned why it's often a good idea to use an existing library where practical!

Python Variable For Get Request?

I am trying to move over some API calls I had working over to python from postman, I am having some issues making a variable callable by my next get request. I've found a few things while searching but never found a 100% answer on how to call the environment variable in the get request...is it correct to use the {{TEST}} to call that var. Example below.
Test = Myaccoount
Json_Response_Test = requests.get('https://thisisjustatesttoaccessmyaccount/{{Test}}')
How can I carry over Test into the request?

Your code will almost work as you have it if you use the feature of newer version of Python called "format strings". These are denoted by a f at the beginning of the string. This works like this in such versions of Python:
Test = Myaccoount
Json_Response_Test = requests.get(f'https://thisisjustatesttoaccessmyaccount/{Test}')
as long as Myaccoount is a valid value that can be expanded by Python into the format string.
If you're using an older version of Python, you could do something like this:
Test = Myaccoount
Json_Response_Test = requests.get('https://thisisjustatesttoaccessmyaccount/{}'.format(Test))
BTW, it's not good form to use uppercase first character names for variables. The convention is to use uppercase only for class and type names, and use lowercase for variable and field names.

Python-How to execute code and store into variable?

So I have been struggling with this issue for what seems like forever now (I'm pretty new to Python). I am using Python 3.7 (need it to be 3.7 due to variations in the versions of packages I am using for the project) to develop an AI chatbot system that can converse with you based on your text input. The program reads the contents of a series of .yml files when it starts. In one of the .yml files I am developing a syntax for when the first 5 characters match a ^###^ pattern, it will instead execute the code and return the result of that execution rather than just output text back to the user. For example:
Normal Conversation:
- - What is AI?
- Artificial Intelligence is the branch of engineering and science devoted to constructing machines that think.
Service/Code-based conversation:
- - Say hello to me
- ^###^print("HELLO")
The idea is that when you ask it to say hello to you, the ^##^print("HELLO") string will be retrieved from the .yml file, the first 5 characters of the response will be removed, the response will be sent to a separate function in the python code where it will run the code and store the result into a variable which will be returned from the function into a variable that will give the nice, clean result of HELLO to the user. I realize that this may be a bit hard to follow, but I will straighten up my code and condense everything once I have this whole error resolved. As a side note: Oracle is just what I am calling the project. I'm not trying to weave Java into this whole mess.
THE PROBLEM is that it does not store the result of the code being run/executed/evaluated into the variable like it should.
My code:
def executecode(input):
print("The code to be executed is: ",input)
#note: the input may occasionally have single quotes and/or double quotes in the input string
result = eval("{}".format(input))
print ("The result of the code eval: ", result)
test = eval("2+2")
test
print(test)
return result
#app.route("/get")
def get_bot_response():
userText = request.args.get('msg')
print("Oracle INTERPRETED input: ", userText)
ChatbotResponse = str(english_bot.get_response(userText))
print("CHATBOT RESPONSE VARIABLE: ", ChatbotResponse)
#The interpreted string was a request due to the ^###^ pattern in front of the response in the custom .yml file
if ChatbotResponse[:5] == '^###^':
print("---SERVICE REQUEST---")
print(executecode(ChatbotResponse[5:]))
interpreter_response = executecode(ChatbotResponse[5:])
print("Oracle RESPONDED with: ", interpreter_response)
else:
print("Oracle RESPONDED with: ", ChatbotResponse)
return ChatbotResponse
When I run this code, this is the output:
Oracle INTERPRETED input: How much RAM do you have?
CHATBOT RESPONSE VARIABLE: ^###^print("HELLO")
---SERVICE REQUEST---
The code to be executed is: print("HELLO")
HELLO
The result of the code eval: None
4
None
The code to be executed is: print("HELLO")
HELLO
The result of the code eval: None
4
Oracle RESPONDED with: None
Output on the website interface
Essentially, need it to say HELLO for the "The result of the code eval:" output. This should get it to where the chatbot responds with HELLO in the web interface, which is the end goal here. It seems as if it IS executing the code due to the HELLO's after the "The code to be executed is:" output text. It's just not storing it into a variable like I need it to.
I have tried eval, exec, ast.literal_eval(), converting the input to string with str(), changing up the single and double quotes, putting \ before pairs of quotes, and a few other things. Whenever I get it to where the program interprets "print("HELLO")" when it executes the code, it complains about the syntax. Also, from several days of looking online I have figured out that exec and eval aren't generally favored due to a bunch of issues, however I genuinely do not care about that at the moment because I am trying to make something that works before I make something that is good and works. I have a feeling the problem is something small and stupid like it always is, but I have no idea what it could be. :(
I used these 2 resources as the foundation for the whole chatbot project:
Text Guide
Youtube Guide
Also, I am sorry for the rather lengthy and descriptive question. It's rare that I have to ask a question of my own on stackoverflow because if I have a question, it usually already has a good answer. It feels like I've tried everything at this point. If you have a better suggestion of how to do this whole system or you think I should try approaching this another way, I'm open to ideas.
Thank you for any/all help. It is very much appreciated! :)

The issue is that python's print() doesn't have a return value, meaning it will always return None. eval simply evaluates some expression, and returns back the return value from that expression. Since print() returns None, an eval of some print statement will also return None.
>>> from_print = print('Hello')
Hello
>>> from_eval = eval("print('Hello')")
Hello
>>> from_print is from_eval is None
True
What you need is a io stream manager! Here is a possible solution that captures any io output and returns that if the expression evaluates to None.
from contextlib import redirect_stout, redirect_stderr
from io import StringIO
# NOTE: I use the arg name `code` since `input` is a python builtin
def executecodehelper(code):
# Capture all potential output from the code
stdout_io = StringIO()
stderr_io = StringIO()
with redirect_stdout(stdout_io), redirect_stderr(stderr_io):
# If `code` is already a string, this should work just fine without the need for formatting.
result = eval(code)
return result, stdout_io.getvalue(), stderr_io.getvalue()
def executecode(code):
result, std_out, std_err = executecodehelper(code)
if result is None:
# This code didn't return anything. Maybe it printed something?
if std_out:
return std_out.rstrip() # Deal with trailing whitespace
elif std_err:
return std_err.rstrip()
else:
# Nothing was printed AND the return value is None!
return None
else:
return result
As a final note, this approach is heavily linked to eval since eval can only evaluate a single statement. If you want to extend your bot to multiple line statements, you will need to use exec, which changes the logic. Here's a great resource detailing the differences between eval and exec: What's the difference between eval, exec, and compile?

It is easy just convert try to create a new list and add the the updated values of that variable to it, for example:
if you've a variable name myVar store the values or even the questions no matter.
1- First declare a new list in your code as below:
myList = []
2- If you've need to answer or display the value through myVar then you can do like below:
myList.append(myVar)
and this if you have like a generator for the values instead if you need the opposite which means the values are already stored then you will just update the second step to be like the following:
myList[0]='The first answer of the first question'
myList[1]='The second answer of the second question'
ans here all the values will be stored in your list and you can also do this in other way, for example using loops is will be much better if you have multiple values or answers.

Strip prefix from all variable names in SPSS

I have a similar question as asked here (Strip suffix from all variable names in SPSS) and the answers there already helped a lot but there is still one question remaining.
I have a dataset in which every variable name has the prefix "v23_1_". I want to remove this prefix from all variables, but there are hundreds of them, so I am looking for a way to do it without using the RENAME statement hundreds of times.
I used this code:
begin program.
vdict=spssaux.VariableDict()
mylist=vdict.range(start="v23_1_dg_mnpdocid", end="v23_1_phq9t0_asku3t0")
nvars = len(mylist)
for i in range(nvars):
myvar = mylist[i]
mynewvar = myvar.strip("v23_1_")
spss.Submit(r"""
rename variables ( %s = %s) .
""" %(myvar, mynewvar))
end program.
Here is a list of the first few variables:
v23_1_dg_mnppusid
v23_1_dg_sigstatus
v23_1_dg_mnpvsno
v23_1_dg_mnpvslbl
v23_1_dg_mnpcvpid
v23_1_dg_mnpvisid
v23_1_dg_mnpvisno
v23_1_dg_mnpvispdt
v23_1_dg_mnpvisfdt
v23_1_dg_mnpfs0
v23_1_dg_mnpfs1
v23_1_dg_mnpfs2
v23_1_dg_mnpfs3
v23_1_dg_mnpfcs0
v23_1_dg_mnpfcs1
v23_1_dg_mnpfcs2
It worked ok for the first variables but then stopped with the message "renaming has created two variables named dg_mnpfs". But the next variable would after stripping has the name "dg_mnpfs2". What has happened is that the 1 at the end in "v23_1_dg_mnpfs1" gets deleted too. And then it propbably intends to also delete the 2 at the end in "v23_1_dg_mnpfs2", which will then lead to the same variable. I don't understand why this is happening and how I can avoid it.
Thanks a lot for your support!
Kind regards,
Beate

As you syntax looks right now, it will run on a variable-by-variable basis. You are submitting/running the RENAME VARIABLES command as many times as the number of variables in your list.
On one hand, this is in-efficient, as it takes longer to run than what I am suggesting below.
On the other (and more important) hand, doing it variable by variable, does not guard against duplicate variables. I am guessing that you already have in your datafile a variable named dg_mnpfs, and you are attempting to create a new one by renaming v23_1_dg_mnpfs. Just check your datafile, after your python code breaks.
A more efficient way of writing you code would be to create lists with the old names, and new names, and submit the syntax with only one command.
begin program.
import spss,spssaux
vdict=spssaux.VariableDict()
mylist=vdict.range(start="v23_1_dg_mnpdocid", end="v23_1_phq9t0_asku3t0")
nvars = len(mylist)
my_new_list=[]
for i in range(nvars):
myvar = mylist[i]
mynewvar = myvar.strip("v23_1_")
my_new_list.append(mynewvar)
my_syntax="ren var (" + " ".join(mylist) + "=" + " ".join(my_new_list) +")."
spss.Submit(my_syntax)
end program.
And one more thing: the strip function removes the text from both ends of the variables. If you only want to remove the prefix, consider using lstrip. Details can be found here, in the official documentation.

Here's a version of the process using SPSS macro. Using SPSSINC SELECT VARIABLES lets you get the whole list of all relevant variables, whatever order they are in, without naming them in the command:
*this is just to create a sample data to play with.
data list list/v23_1_var1 to v23_1_var6.
begin data
end data.
The following creates a list of the relevant variables:
SPSSINC SELECT VARIABLES MACRONAME="!list" /PROPERTIES PATTERN = "v23_1_*".
* the following macro creates one rename command for all the list.
define !doRename ()
rename variables (!eval(!list)=!do !i !in(!eval(!list)) !substr(!i, 7) !doend).
!enddefine.
!doRename .

Incremental Saves

I am trying to write up a script on incremental saves but there are a few hiccups that I am running into.
If the file name is "aaa.ma", I will get the following error - ValueError: invalid literal for int() with base 10: 'aaa' # and it does not happens if my file is named "aaa_0001"
And this happens if I wrote my code in this format: Link
As such, to rectify the above problem, I input in an if..else.. statement - Link, it seems to have resolved the issue on hand, but I was wondering if there is a better approach to this?
Any advice will be greatly appreciated!

Use regexes for better flexibility especially for file rename scripts like these.
In your case, since you know that the expected filename format is "some_file_name_<increment_number>", you can use regexes to do the searching and matching for you. The reason we should do this is because people/users may are not machines, and may not stick to the exact naming conventions that our scripts expect. For example, the user may name the file aaa_01.ma or even aaa001.ma instead of aaa_0001 that your script currently expects. To build this flexibility into your script, you can use regexes. For your use case, you could do:
# name = lastIncFile.partition(".")[0] # Use os.path.split instead
name, ext = os.path.splitext(lastIncFile)
import re
match_object = re.search("([a-zA-Z]*)_*([0-9]*)$", name)
# Here ([a-zA-Z]*) would be group(1) and would have "aaa" for ex.
# and ([0-9]*) would be group(2) and would have "0001" for ex.
# _* indicates that there may be an _, or not.
# The $ indicates that ([0-9]*) would be the LAST part of the name.
padding = 4 # Try and parameterize as many components as possible for easy maintenance
default_starting = 1
verName = str(default_starting).zfill(padding) # Default verName
if match_object: # True if the version string was found
name = match_object.group(1)
version_component = match_object.group(2)
if version_component:
verName = str(int(version_component) + 1).zfill(padding)
newFileName = "%s_%s.%s" % (name, verName, ext)
incSaveFilePath = os.path.join(curFileDir, newFileName)
Check out this nice tutorial on Python regexes to get an idea what is going on in the above block. Feel free to tweak, evolve and build the regex based on your use cases, tests and needs.
Extra tips:
Call cmds.file(renameToSave=True) at the beginning of the script. This will ensure that the file does not get saved over itself accidentally, and forces the script/user to rename the current file. Just a safety measure.
If you want to go a little fancy with your regex expression and make them more readable, you could try doing this:
match_object = re.search("(?P<name>[a-zA-Z]*)_*(?P<version>[0-9]*)$", name)
name = match_object.group('name')
version_component = match_object('version')
Here we use the ?P<var_name>... syntax to assign a dict key name to the matching group. Makes for better readability when you access it - mo.group('version') is much more clearer than mo.group(2).
Make sure to go through the official docs too.
Save using Maya's commands. This will ensure Maya does all it's checks while and before saving:
cmds.file(rename=incSaveFilePath)
cmds.file(save=True)
Update-2:
If you want space to be checked here's an updated regex:
match_object = re.search("(?P<name>[a-zA-Z]*)[_ ]*(?P<version>[0-9]*)$", name)
Here [_ ]* will check for 0 - many occurrences of _ or (space). For more regex stuff, trying and learn on your own is the best way. Check out the links on this post.
Hope this helps.