File processing

[Gopal]

Hello,

I'm Gopal. I'm looking for a solution to the following problem:

I need to create a text file config.txt having some parameters. I'm
thinking of going with this format by having "Param Name - value". Note
that the value is a string/number; something like this:

PROJECT_ID = "E4208506"
SW_VERSION = "18d"
HW_VERSION = "2"

In my script, I need to parse this config file and extract the Values
of the parameters.

I'm very new to python as you can understand from the problem. However,
I've some project dealines. So I need your help in arriving at a simple
and ready-made solution.

Regards,
Gopal.

[wittempj@hotmail.com]

Re: File processing

The ConfigParser class is designed for this task, see

http://docs.python.org/lib/module-ConfigParser.html

[Jeremy Jones]

Re: File processing

Gopal wrote:
[color=blue]
>Hello,
>
>I'm Gopal. I'm looking for a solution to the following problem:
>
>I need to create a text file config.txt having some parameters. I'm
>thinking of going with this format by having "Param Name - value". Note
>that the value is a string/number; something like this:
>
>PROJECT_ID = "E4208506"
>SW_VERSION = "18d"
>HW_VERSION = "2"
>
>In my script, I need to parse this config file and extract the Values
>of the parameters.
>
>I'm very new to python as you can understand from the problem. However,
>I've some project dealines. So I need your help in arriving at a simple
>and ready-made solution.
>
>Regards,
>Gopal.
>
>
>[/color]
Would this
(http://www.python.org/doc/current/li...figParser.html) do what
you need? It's part of the standard library.


- JMJ

[Gopal]

Re: File processing

Thanks for the reference. However, I'm not understanding how to use it.
Could you please provide with an example? Like I open the file, read
line and give it to parser?

Please help me.

[Peter Hansen]

Re: File processing

Gopal wrote:[color=blue]
> Hello,
>
> I'm Gopal. I'm looking for a solution to the following problem:
>
> I need to create a text file config.txt having some parameters. I'm
> thinking of going with this format by having "Param Name - value". Note
> that the value is a string/number; something like this:
>
> PROJECT_ID = "E4208506"
> SW_VERSION = "18d"
> HW_VERSION = "2"
>
> In my script, I need to parse this config file and extract the Values
> of the parameters.
>
> I'm very new to python as you can understand from the problem. However,
> I've some project dealines. So I need your help in arriving at a simple
> and ready-made solution.[/color]

Luckily, you're already done! Just make sure the above file has a .py
extension, say maybe "config.py" , and then in code where you need to
"parse" it and extract the values you can just do this:

import config
print 'Project Id is', config.PROJECT_ ID

-Peter

[Gopal]

Re: File processing

Thank you very much. That works!!!

[Jeremy Jones]

Re: File processing

Gopal wrote:
[color=blue]
>Thanks for the reference. However, I'm not understanding how to use it.
>Could you please provide with an example? Like I open the file, read
>line and give it to parser?
>
>Please help me.
>
>
>[/color]
I had thought of recommending what Peter Hansen recommended - just
importing the text you have as a Python module. I don't know why I
recommended ConfigParser over that option. However, if you don't like
what Peter said and would still like to look at ConfigParser, here is a
very simple example. Here is the config file I created from your email:

jmjones@qiwi 8:36AM configparser % cat foo.txt
[main]
PROJECT_ID = "E4208506"
SW_VERSION = "18d"
HW_VERSION = "2"


Here is me running ConfigParser from a Python shell:

In [1]: import ConfigParser

In [2]: p = ConfigParser.Co nfigParser()

In [3]: p.read("foo.txt ")
Out[3]: ['foo.txt']

In [4]: p.get("main", "PROJECT_ID ")
Out[4]: '"E4208506"'


Note that the value of ("main", "PROJECT_ID ") is a string which contains
double quotes in it. If you take Peter's advice, you won't have that
problem; the config file will preserve your types for you.

HTH,

- JMJ

[Bryan Olson]

Re: File processing

Peter Hansen wrote:[color=blue]
> Gopal wrote:[color=green]
>> [...] I'm
>> thinking of going with this format by having "Param Name - value". Note
>> that the value is a string/number; something like this:
>>
>> PROJECT_ID = "E4208506"
>> SW_VERSION = "18d"
>> HW_VERSION = "2"
>>
>> In my script, I need to parse this config file and extract the Values
>> of the parameters.[/color][/color]
[color=blue]
> Luckily, you're already done! Just make sure the above file has a .py
> extension, say maybe "config.py" , and then in code where you need to
> "parse" it and extract the values you can just do this:
>
> import config
> print 'Project Id is', config.PROJECT_ ID[/color]

In many cases that's fine, but at least be aware that the party
supplying the config data also gets the ability to change
the behavior of the process in ways of his choosing.


--
--Bryan