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django admin - add custom form fields that are not part of the model
....models import YourModel
class YourModelForm(forms.ModelForm):
extra_field = forms.CharField()
def save(self, commit=True):
extra_field = self.cleaned_data.get('extra_field', None)
# ...do something with extra_field here...
return super(YourModelForm, self).save(c...
Test if lists share any items in python
...
def lists_overlap3(a, b):
return bool(set(a) & set(b))
Note: the above assumes that you want a boolean as the answer. If all you need is an expression to use in an if statement, just use if set(a) & set(b):
...
Getting a map() to return a list in Python 3.x
...o be ASCII/latin-1 is to do bulk conversions at the C layer: bytes(sequence_of_ints_in_range_0_to_256).decode('latin-1') which makes a str faster by avoiding Python function calls for each element in favor of a bulk conversion of all elements using only C level function calls. You can wrap the above...
Calling a function of a module by using its name (a string)
...
Assuming module foo with method bar:
import foo
method_to_call = getattr(foo, 'bar')
result = method_to_call()
You could shorten lines 2 and 3 to:
result = getattr(foo, 'bar')()
if that makes more sense for your use case.
You can use getattr in this fashion on class insta...
Get notified when UITableView has finished asking for data?
...interface declaration for UITableView, you will find NSMutableArray member _reloadItems right under _insertItems and _deleteItems. (I've had to rework code I inherited because of this change.)
– Walt Sellers
Feb 21 '13 at 6:32
...
Regex to validate password strength
...ng some of your rules to:
Add more special characters i.e. %, ^, (, ), -, _, +, and period. I'm adding all the special characters that you missed above the number signs in US keyboards. Escape the ones regex uses.
Make the password 8 or more characters. Not just a static number 8.
With the above i...
Union of dict objects in Python [duplicate]
...
How is tmp = dict(y); tmp.update(x); do_something(tmp) simpler?
– Mechanical snail
Aug 7 '12 at 6:04
7
...
adding noise to a signal in python
...umpy as np
import matplotlib.pyplot as plt
t = np.linspace(1, 100, 1000)
x_volts = 10*np.sin(t/(2*np.pi))
plt.subplot(3,1,1)
plt.plot(t, x_volts)
plt.title('Signal')
plt.ylabel('Voltage (V)')
plt.xlabel('Time (s)')
plt.show()
x_watts = x_volts ** 2
plt.subplot(3,1,2)
plt.plot(t, x_watts)
plt.title...
Importing a CSV file into a sqlite3 database table using Python
...csv, sqlite3
con = sqlite3.connect(":memory:") # change to 'sqlite:///your_filename.db'
cur = con.cursor()
cur.execute("CREATE TABLE t (col1, col2);") # use your column names here
with open('data.csv','r') as fin: # `with` statement available in 2.5+
# csv.DictReader uses first line in file fo...
Can you give a Django app a verbose name for use throughout the admin?
... the 1.8 docs (and current docs),
New applications should avoid default_app_config. Instead they should require the dotted path to the appropriate AppConfig subclass to be configured explicitly in INSTALLED_APPS.
Example:
INSTALLED_APPS = [
# ...snip...
'yourapp.apps.YourAppConfig',
]...