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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!
Related
I need to grab a url from a text file.
The URL is stored in a string like so: 'URL=http://example.net'.
Is there anyway I could grab everything after the = char up until the . in '.net'?
Could I use the re module?
text = """A key feature of effective analytics infrastructure in healthcare is a metadata-driven architecture. In this article, three best practice scenarios are discussed: https://www.healthcatalyst.com/clinical-applications-of-machine-learning-in-healthcare Automating ETL processes so data analysts have more time to listen and help end users , https://www.google.com/, https://www.facebook.com/, https://twitter.com
code below catches all urls in text and returns urls in list."""
urls = re.findall('(?:(?:https?|ftp):\/\/)?[\w/\-?=%.]+\.[\w/\-?=%.]+', text)
print(urls)
output:
[
'https://www.healthcatalyst.com/clinical-applications-of-machine-learning-in-healthcare',
'https://www.google.com/',
'https://www.facebook.com/',
'https://twitter.com'
]
i dont have much information but i will try to help with what i got im assuming that URL= is part of the string in that case you can do this
re.findall(r'URL=(.*?).', STRINGNAMEHERE)
Let me go more into detail about (.*?) the dot means Any character (except newline character) the star means zero or more occurences and the ? is hard to explain but heres an example from the docs "Causes the resulting RE to match 0 or 1 repetitions of the preceding RE. ab? will match either ‘a’ or ‘ab’." the brackets place it all into a group. All this togethear basicallly means it will find everything inbettween URL= and .
You don't need RegEx'es (the re module) for such a simple task.
If the string you have is of the form:
'URL=http://example.net'
Then you can solve this using basic Python in numerous ways, one of them being:
file_line = 'URL=http://example.net'
start_position = file_line.find('=') + 1 # this gives you the first position after =
end_position = file_line.find('.')
# this extracts from the start_position up to but not including end_position
url = file_line[start_position:end_position]
Of course that this is just going to extract one URL. Assuming that you're working with a large text, where you'd want to extract all URLs, you'll want to put this logic into a function so that you can reuse it, and build around it (achieve iteration via the while or for loops, and, depending on how you're iterating, keep track of the position of the last extracted URL and so on).
Word of advice
This question has been answered quite a lot on this forum, by very skilled people, in numerous ways, for instance: here, here, here and here, to a level of detail that you'd be amazed. And these are not all, I just picked the first few that popped up in my search results.
Given that (at the time of posting this question) you're a new contributor to this site, my friendly advice would be to invest some effort into finding such answers. It's a crucial skill, that you can't do without in the world of programming.
Remember, that whatever problem it is that you are encountering, there is a very high chance that somebody on this forum had already encountered it, and received an answer, you just need to find it.
Please try this. It worked for me.
import re
s='url=http://example.net'
print(re.findall(r"=(.*)\.",s)[0])
I have a config file that I'm reading using the following code:
import configparser as cp
config = cp.ConfigParser()
config.read('MTXXX.ini')
MT=identify_MT(msgtext)
schema_file = config.get(MT,'kbfile')
fold_text = config.get(MT,'fold')
The relevant section of the config file looks like this:
[536]
kbfile=MT536.kb
fold=:16S:TRANSDET\n
Later I try to find text contained in a dictionary that matches the 'fold' parameter, I've found that if I find that text using the following function:
def test (find_text)
return {k for k, v in dictionary.items() if find_text in v}
I get different results if I call that function in one of two ways:
test(fold_text)
Fails to find the data I want, but:
test(':16S:TRANSDET\n')
returns the results I know are there.
And, if I print the content of the dictionary, I can see that it is, as expected, shown as
:16S:TRANSDET\n
So, it matches when I enter the search text directly, but doesn't find a match when I load the same text in from a config file.
I'm guessing that there's some magic being applied here when reading/handling the \n character pattern in from the config file, but don't know how to get it to work the way I want it to.
I want to be able to parameterise using escape characters but it seems I'm blocked from doing this due to some internal mechanism.
Is there some switch I can apply to the config reader, or some extra parsing I can do to get the behavior I want? Or perhaps there's an alternate solution. I do find the configparser module convenient to use, but perhaps this is a limitation that requires an alternative, or even self-built module to lift data out of a parameter file.
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.
I have data coming in to a python server via a socket. Within this data is the string '<port>80</port>' or which ever port is being used.
I wish to extract the port number into a variable. The data coming in is not XML, I just used the tag approach to identifying data for future XML use if needed. I do not wish to use an XML python library, but simply use something like regexp and strings.
What would you recommend is the best way to match and strip this data?
I am currently using this code with no luck:
p = re.compile('<port>\w</port>')
m = p.search(data)
print m
Thank you :)
Regex can't parse XML and shouldn't be used to parse fake XML. You should do one of
Use a serialization method that is nicer to work with to start with, such as JSON or an ini file with the ConfigParser module.
Really use XML and not something that just sort of looks like XML and really parse it with something like lxml.etree.
Just store the number in a file if this is the entirety of your configuration. This solution isn't really easier than just using JSON or something, but it's better than the current one.
Implementing a bad solution now for future needs that you have no way of defining or accurately predicting is always a bad approach. You will be kept busy enough trying to write and maintain software now that there is no good reason to try to satisfy unknown future needs. I have never seen a case where "I'll put this in for later" has led to less headache later on, especially when I put it in by doing something completely wrong. YAGNI!
As to what's wrong with your snippet other than using an entirely wrong approach, angled brackets have a meaning in regex.
Though Mike Graham is correct, using regex for xml is not 'recommended', the following will work:
(I have defined searchType as 'd' for numerals)
searchStr = 'port'
if searchType == 'd':
retPattern = '(<%s>)(\d+)(</%s>)'
else:
retPattern = '(<%s>)(.+?)(</%s>)'
searchPattern = re.compile(retPattern % (searchStr, searchStr))
found = searchPattern.search(searchStr)
retVal = found.group(2)
(note the complete lack of error checking, that is left as an exercise for the user)
I am looking for a way to extract / scrape data from Word files into a database. Our corporate procedures have Minutes of Meetings with clients documented in MS Word files, mostly due to history and inertia.
I want to be able to pull the action items from these meeting minutes into a database so that we can access them from a web-interface, turn them into tasks and update them as they are completed.
Which is the best way to do this:
VBA macro from inside Word to create CSV and then upload to the DB?
VBA macro in Word with connection to DB (how does one connect to MySQL from VBA?)
Python script via win32com then upload to DB?
The last one is attractive to me as the web-interface is being built with Django, but I've never used win32com or tried scripting Word from python.
EDIT: I've started extracting the text with VBA because it makes it a little easier to deal with the Word Object Model. I am having a problem though - all the text is in Tables, and when I pull the strings out of the CELLS I want, I get a strange little box character at the end of each string. My code looks like:
sFile = "D:\temp\output.txt"
fnum = FreeFile
Open sFile For Output As #fnum
num_rows = Application.ActiveDocument.Tables(2).Rows.Count
For n = 1 To num_rows
Descr = Application.ActiveDocument.Tables(2).Cell(n, 2).Range.Text
Assign = Application.ActiveDocument.Tables(2).Cell(n, 3).Range.Text
Target = Application.ActiveDocument.Tables(2).Cell(n, 4).Range.Text
If Target = "" Then
ExportText = ""
Else
ExportText = Descr & Chr(44) & Assign & Chr(44) & _
Target & Chr(13) & Chr(10)
Print #fnum, ExportText
End If
Next n
Close #fnum
What's up with the little control character box? Is some kind of character code coming across from Word?
Word has a little marker thingy that it puts at the end of every cell of text in a table.
It is used just like an end-of-paragraph marker in paragraphs: to store the formatting for the entire paragraph.
Just use the Left() function to strip it out, i.e.
Left(Target, Len(Target)-1))
By the way, instead of
num_rows = Application.ActiveDocument.Tables(2).Rows.Count
For n = 1 To num_rows
Descr = Application.ActiveDocument.Tables(2).Cell(n, 2).Range.Text
Try this:
For Each row in Application.ActiveDocument.Tables(2).Rows
Descr = row.Cells(2).Range.Text
Well, I've never scripted Word, but it's pretty easy to do simple stuff with win32com. Something like:
from win32com.client import Dispatch
word = Dispatch('Word.Application')
doc = word.Open('d:\\stuff\\myfile.doc')
doc.SaveAs(FileName='d:\\stuff\\text\\myfile.txt', FileFormat=?) # not sure what to use for ?
This is untested, but I think something like that will just open the file and save it as plain text (provided you can find the right fileformat) – you could then read the text into python and manipulate it from there. There is probably a way to grab the contents of the file directly, too, but I don't know it off hand; documentation can be hard to find, but if you've got VBA docs or experience, you should be able to carry them across.
Have a look at this post from a while ago: http://mail.python.org/pipermail/python-list/2002-October/168785.html Scroll down to COMTools.py; there's some good examples there.
You can also run makepy.py (part of the pythonwin distribution) to generate python "signatures" for the COM functions available, and then look through it as a kind of documentation.
You could use OpenOffice. It can open word files, and also can run python macros.
I'd say look at the related questions on the right -->
The top one seems to have some good ideas for going the python route.
how about saving the file as xml. then using python or something else and pull the data out of word and into the database.
It is possible to programmatically save a Word document as HTML and to import the table(s) contained into Access. This requires very little effort.