python

finding max in python as per some custom criterion

Hi, I can do max(s) to find the max of a sequence. But suppose I want to compute max according to my own function , something like so - currmax = 0 def mymax(s) : for i in s : #assume arity() attribute is present currmax = i.arity() if i.arity() > currmax else currmax Is there a clean pythonic way of doing this? Thanks! ...

Methods of sending web-generated config files to servers and restarting services.

Hi, We're writing a web-based tool to configure our services provided by multiple servers. This includes interfaces configuration, dhcp configs etc. etc. Having configs in database and views that generate proper output, how to send it/make it available for servers? I'm thinking about sending it through scp and invoking reload command t...

Trying to figure out URL dispatcher for sluggale URLs like stackoverflow

I'm using the Tornado framework (Python). I have the sluggable URLs working. But I have 3 different entries in the URL dispatcher. I was wondering if someone could help me transform it into one line. This is what I have: (r"/post/([0-9]+)/[a-zA-Z0-9\-]+", SpotHandler), (r"/post/([0-9]+)/", SpotHandler), (r"/post/([0-9]+)", SpotHan...

How to change the app name in OSX menubar in a pure-Python application bundle?

I am trying to create a pure-Python application bundle for a wxPython app. I created the .app directory with the files described in Apple docs, with an Info.plist file etc. The only difference between a "normal" app and this bundle is that the entry point (CFBundleExecutable) is a script which starts with the following line: #!/usr/bin/...

nested for loop

Hello, Just learning Python and trying to do a nested for loop. What I'd like to do in the end is place a bunch of email addresses in a file and have this script find the info, like the sending IP of mail ID. For now i'm testing it on my /var/log/auth.log file Here is my code so far: #!/usr/bin/python # this section puts emails from ...

Change array that might contain None to an array that contains "" in python

I have a python function that gets an array called row. Typically row contains things like: ["Hello","goodbye","green"] And I print it with: print "\t".join(row) Unfortunately, sometimes it contains: ["Hello",None,"green"] Which generates this error: TypeError: sequence item 2: expected string or Unicode, NoneType found Is t...

decorating a function and adding functionalities preserving the number of argument

I'd like to decorate a function, using a pattern like this: def deco(func): def wrap(*a,**kw): print "do something" return func(*a,**kw) return wrap The problem is that if the function decorated has a prototype like that: def function(a,b,c): return When decorated, the prototype is destroyed by the varargs, ...

Server-side SVG to PNG (or some other image format) in python

Currently I'm using rsvg to load the svg (from a string, not from a file) and drawing to cairo. Anyone know a better way? I use PIL elsewhere in my application, but I don't know of a way to do this with PIL. ...

Letter Count on a string

Python newb here. I m trying to count the number of letter "a"s in a given string. Code is below. It keeps returning 1 instead 3 in string "banana". Any input appreciated. def count_letters(word, char): count = 0 while count <= len(word): for char in word: if char == word[count]: count += 1 ...

How do I use a string as a keyword argument?

Specifically, I'm trying to use a string to arbitrairly filter the ORM. I've tried exec and eval solutions, but I'm running into walls. The code below doesn't work, but it's the best way I know how to explain where I'm trying to go from gblocks.models import Image f = 'image__endswith="jpg"' # Would be scripted in another area, but pa...

Python: Using `copyreg` to define reducers for types that already have reducers

(Keep in mind I'm working in Python 3, so a solution needs to work in Python 3.) I would like to use the copyreg module to teach Python how to pickle functions. When I tried to do it, the _Pickler object would still try to pickle functions using the save_global function. (Which doesn't work for unbound methods, and that's the motivation...

Possible to call single-parameter Python function without using parentheses?

The Python documentation specifies that is is legal to omit the parentheses if a function only takes a single parameter, but myfunction "Hello!" generates a syntax error. So, what's the deal? (I'm using Python 3.1) EDIT: The statement that I read only applies to generator expressions: The parentheses can be omitted on ca...

Filter objects within two seconds of one another using SQLAlchemy

Hello: I have two tables with a column 'date'. One holds (name, date) and the other holds (date, p1, p2). Given a name, I want to use the date in table 1 to query p1 and p2 from table two; the match should happen if date in table one is within two seconds of date in table two. How can you accomplish this using SQLAlchemy? I've tried (u...

Is cropping of jpeg images using the PIL lossless?

A simple questions really. If you crop a jpeg image using the Python Imaging Library, is the resulting image recompressed, or is it lossless? ...

How to write an XML file without header in Python?

Hi, when using Python's stock XML tools such as xml.dom.minidom for XML writing, a file would always start off like <?xml version="1.0"?> [...] While this is perfectly legal XML code, and it's even recommended to use the header, I'd like to get rid of it as one of the programs I'm working with has problems here. I can't seem to find...

OpenCV Python HoughCircles error

Hi, I'm working on a program that detects circular shapes in images. I decided a Hough Transform would be the best, and I found one in the OpenCV library. The problem is that when I try to use it I get an error that I have no idea how to fix. Is OpenCV for Python not fully implemented? Is there a fix to the library I need for the progra...

How do i add a new object with suds?

I'm trying to use suds but have so far been unsuccessful at figuring this out. Hopefully it's something simple that i'm missing. Any help would be highly appreciated. This is supposed to be the raw soap message that i need to achieve: <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:api="http://api.serv...

Email notifications of exceptions happening in a Python app?

UPDATE: This is a Django web app Hi folks, I want to set up email notifications when there is an error happening in my application. In ruby, there is a very elegant solution called ExceptionNotifier, which wraps around the exception handler and uses the built-in mailer to send an email. What is the best way of doing this in Python? I k...

How to set time limit on input

in python, is there a way to, while waiting for a user input, count time so that after, say 30 seconds, the raw_input() function is automatically skipped? ...

Strengths and weaknesses of JIT compilers for Python

Hi there, I'm currently aware of the following Python JIT compilers: Psyco, PyPy and Unladen Swallow. Basically, I'd like to ask for your personal experiences on the strengths and weaknesses of these compilers - and if there are any others worth looking into. Thanks in advance, Az ...