11 March 2013

I’m starting learning Python a bit.

argparse

if you have args setup in different modules, like you want setup --log on logging, setup --tor --skip-tor on requesting, the combination of add_help=False and parse_known_args is pretty cool.

import argparse
parent_argparse = argparse.ArgumentParser(add_help=False)
parent_argparse.add_argument('--log', action='store', default='ERROR', dest='log', help='logging level: DEBUG, INFO, WARNING, ERROR, CRITICAL')
_args, _args_unknown = parent_argparse.parse_known_args()

afterwards, in real place, do

parser = argparse.ArgumentParser(description='Some real CLI', parents=[parent_argparse])

init.py and as

actually it’s a very cool feature. you can put some common code for all sub-modules in __init__.py like config code (to avoid write another file)

import ConfigParser
try:
    cfg = ConfigParser.ConfigParser()
    cfg.read(['/somwhere/conf/project.ini', '/somwhere/conf/project_local.ini'])
except ConfigParser.Error, e:
    logger.critical('Cannot read configuration file, reason [%s]' % e)

and as is pretty amazing.

from modulename import cfg as project_config

BeautifulSoup is another HTML::TreeBuilder

BeautifulSoup works like Perl HTML::TreeBuilder.

from bs4 import BeautifulSoup
soup = BeautifulSoup(text)

for tag in soup.find_all('span', attrs={'id': re.compile('^ctl00_contentPageContent_lbl(.*?)Value$')}):
    id = tag['id']
    id = id.replace('ctl00_contentPageContent_lbl', '').replace('Value', '')
    data[id] = tag.get_text()

something I do like in Python

def with args and default values. (Perl sub was developed too many years ago.)

you don’t need type so many {} or ().

something I do not like in Python

string interpolation is quite inconvenience. there are %, format and Template. but I really miss the $ with Perl.

I miss Perl regexp a lot. the re.compile, re.sub, re.I is too much typing.

Disclaim

I’m still a newbie. so parden me if anything is wrong. I’ll write more when I learn more. and I admit it’s pretty fun to learn Python.



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