Python - tlam/Wiki GitHub Wiki

Check a unicode name

 import unicodedata
 unicodedata.name(u'\u00c3')
 unicodedata.name(u'\u00a9')

Check substring in string

 if 'Hi' in 'Hi There':
     print 'Success!'

gaierror

 socket.gaierror: [Errno -2] Name or service not known

Make sure that your ethernet or wireless is connected to the network or internet.

Tracing a script
```
 python -m trace --trace test.py
```
Profile module not present
```
 sudo apt-get install python-profiler
```
Set sys encoding to utf-8 on Python 2.7.5, OSX 10.8 in your virtualenv. Create .virtualenvs/compass/lib/python2.7/sitecustomize.py with:
```
 import sys
 sys.setdefaultencoding('utf-8')
```

Printing JSON in the order the keys are originally ordered:

 import collections
 import json
 import pprint

 pprint.pprint(json.loads('{"hello": "world"}', object_pairs_hook=collections.OrderedDict).items())

String format number of decimal places:
```
 >>> '{:.2f}'.format(3.145678)
 '3.14'
```

String format date:

 >>> from datetime import datetime
 >>> '{:%Y-%m-%d}'.format(datetime.now())
 '2013-11-28'

Rounding up to 2dp:

 import math

 value = 416.325
 print(math.ceil(value * 100) / 100.00)  # 416.33

Commands

Install into a specific python version
```
 easy_install-2.6 south
```

virtualenv

sudo apt-get install python-pip
sudo pip install virtualenv
sudo pip install virtualenvwrapper

Update your environment with the following, .bashrc or .bash_profile:

 export WORKON_HOME=$HOME/.virtualenvs
 source /usr/local/bin/virtualenvwrapper.sh

Create $HOME/.virtualenvs
Create your dev environment:
```
 mkvirtualenv dev
```

Alternate way to activate

 source .virtualenvs/django/bin/activate

Create a virtualenv with python3 bin inside it

 mkvirtualenv -p `which python3` apython3virtualenv

pip

Install requirements.txt
```
 pip install -r requirements.txt
```
When installing from the requirements.txt, pip will download each package and build it. Once all the packages have been successfully downloaded and built will they all be installed in one go. If at any point, download failed or the build failed, none of the packages will be installed.

PyFlakes

PyFlakes is a great tool to clean up your code but it has some options lacking such as ignoring certain folders or warnings.

Nose

Run a specific test in file test_something.py with class TestSomething specific test test_somewhere:
```
 nosetests test_something:TestSomething.test_somewhere
```

Remove print suppression:

 nosetests --nocapture test_something:TestSomething.test_somewhere
 nosetests -s test_something:TestSomething.test_somewhere

pep8

Ignoring a specific warning, for example E501 line too long (90 characters):
```
 pep8 --ignore=E501 models.py
```

SOAP with requests

from lxml import etree, objectify
import requests


def clean(content):
    root = objectify.fromstring(content)
    for elem in root.getiterator():
        i = elem.tag.find('}')
        if i >= 0:
            elem.tag = elem.tag[i + 1:]
    objectify.deannotate(root, cleanup_namespaces=True)
    return root

headers = {
    'Content-Type': 'text/xml; charset=utf-8',
    'SOAPAction': 'yoururl/YourAction',
}

url = 'soapurl'
msg = 'yourrequest'
response = requests.post(url, data=msg, headers=headers, verify=False)
root = clean(response.content)

SNI support for Python 2.7.3

SNI is currently only supported in Python 2.7.9 but we use 2.7.3

Use Python OpenSSL
```
 pip install pyopenssl ndg-httpsclient pyasn1
```
1. Additional dependency with the above, check if libffi-dev is installed:
```
 apt-cache policy libffi-dev
```
  If it is not present, you can install it with:
```
 sudo apt-get install libffi-dev
```
Upgrade to latest requests 2.6.0 if your requests < 2.2.1

After installing all the above, python requests will use Python OpenSSL instead of the default SSL lib.