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Python – Filter directory contents

COMP-E — Mon, 28 Mar 2011 02:55:23 +0000

short and sweet, this python snippet will return a list containing your filtered directory

import re import os


filter = ".*" + searchstr + ".*"

m = re.compile(filter,re.I) #if you want to ignore case use re.I, otherwise remove it

filter(m.search,os.listdir(os.getcwd()))

#that's it, you can see that the reason for compiling the regex is so you can use m.search as a function pointer which accepts the list of all items in the directory

Python – Use regex to split hyphenated words

COMP-E — Mon, 28 Mar 2011 02:41:17 +0000

I was asked this question on stackoverflow, and figured I’d repost it here since I wrote it after all. s = "-this is. A - sentence;one-word what's" re.findall("\w+-\w+|[\w']+",s) result: ['this', 'is', 'A', 'sentence', 'one-word', "what's"] make sure you notice that … Continue reading →

Python – Chunk string or data buffer

COMP-E — Mon, 28 Mar 2011 02:33:16 +0000

I was disappointed that there was no good way to chunk up data for string formatting or packetzing UDP data. After a bit of thought, and a desire to avoid using python code to do loops, I came up with a nice simple regex-based solution.
import re buff = #some data buffer m = re.compile(r'.{##}|.+',re.S) chunks = m.findall(buff)

example: >>> import re >>> m = re.compile(r'.{5}|.*',re.S) >>> data = "HELLO_WORLD_HOW_ARE_YOU" >>> m.findall(data) ['HELLO', '_WORL', 'D_HOW', '_ARE_', 'YOU']

I would assume that this is the most efficient way to do this, as it uses underlying c functions, and there’s nothing better than zippy python : )

Python – Convert 16bit image to 24bit image 565 to 888

COMP-E — Mon, 28 Mar 2011 02:12:34 +0000

Doing the following is much better than using putpixel and a for loop, as numpy uses c-functions. The actual execution speed is about .3 seconds faster on a 240×320 RGBA image.

import numpy as np arr = np.fromstring(buff,dtype=np.uint16).astype(np.uint32) arr = 0xFF000000 + ((arr & 0xF800) >> 8 ) + ((arr & 0x07E0) << 5) + ((arr & 0x001F) << 19) return Image.frombuffer('RGBA', (xdim,ydim), arr, 'raw', 'RGBA', 0, 1)

While it may seem like an odd bit shift, stuffing the channels into an int requires that it get stuffed as (most significant bit) ABGR (least significant bit). If you were to use the PIL call to putpixel, it would get stuffed as RGBA.

Pythons in the ‘C’ircus

COMP-E — Thu, 06 Aug 2009 06:39:59 +0000

Spiffy code that is. Stubby has made a few contributions as of late, so check them out. I will be ragging on him to put his battleship game up, but alas it seems it’s lacking comments so we’ll see how long that takes.

I on the other hand, appologize for not tossing up any new coding examples. As of late I’ve been rather busy but fear not for I’ve been dabbling in Python and have some fun stuff to share. To give a bit of a hint, I’ve been playing with the Numpy module and have found it incredibly useful as it ties in exceptionally well with Matlab. I also plan on making a mini program to poll USB for those of you who rely on antiquated RS232 and are left without an easy means of switching over : )

Lastly, I encourage more of you to join and contribute well documented examples to the site. As always, there are no ads and questions will be answered without the arrogant charm of other such code collaborative sites