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Is there an expression for an infinite generator?
...te itertools.count: count = lambda start=0, step=1: (start + i*step for i, _ in enumerate(iter(int, 1)))
– Coffee_Table
Aug 13 '18 at 23:43
2
...
How to list imported modules?
...ems():
if isinstance(val, types.ModuleType):
yield val.__name__
This won't return local imports, or non-module imports like from x import y. Note that this returns val.__name__ so you get the original module name if you used import module as alias; yield name instead if you wa...
How do I execute a string containing Python code in Python?
....stderr = codeErr
exec code
# restore stdout and stderr
sys.stdout = sys.__stdout__
sys.stderr = sys.__stderr__
print f(4)
s = codeErr.getvalue()
print "error:\n%s\n" % s
s = codeOut.getvalue()
print "output:\n%s" % s
codeOut.close()
codeErr.close()
...
What is the documents directory (NSDocumentDirectory)?
...lowing tech note: https://developer.apple.com/library/ios/technotes/tn2406/_index.html
The Apple sanctioned way (from the link above) is as follows:
// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
{
return [[[NSFileManager defaultManager] U...
How does Django's Meta class work?
...n [2]: User.Meta
Out[2]: django.contrib.auth.models.Meta
In [3]: User.Meta.__dict__
Out[3]:
{'__doc__': None,
'__module__': 'django.contrib.auth.models',
'abstract': False,
'verbose_name': <django.utils.functional.__proxy__ at 0x26a6610>,
'verbose_name_plural': <django.utils.functional...
PHP Pass variable to next page
...n cookies. More secure, but not completely secure.
Session:
//On page 1
$_SESSION['varname'] = $var_value;
//On page 2
$var_value = $_SESSION['varname'];
Remember to run the session_start(); statement on both these pages before you try to access the $_SESSION array, and also before any output i...
What is the most pythonic way to check if an object is a number?
...: 0 + x
except TypeError: canadd=False
else: canadd=True
The presence of __add__ per se tells you nothing useful, since e.g all sequences have it for the purpose of concatenation with other sequences. This check is equivalent to the definition "a number is something such that a sequence of such t...
What is the proper way to comment functions in Python?
...odule, function, class, or method definition. Such a docstring becomes the __doc__ special attribute of that object.
All modules should normally have docstrings, and all functions and classes exported by a module should also have docstrings. Public methods (including the __init__ constructor) s...
What is the most efficient way to store a list in the Django models?
...
See docs.djangoproject.com/en/3.0/topics/db/examples/many_to_one
– Jon Ison
Jul 2 at 9:42
...
Bash continuation lines
...here document. (Line terminators will still remain, though.)
cat <<-____HERE
continuation
lines
____HERE
See also http://ss64.com/bash/syntax-here.html
If you need to preserve some, but not all, leading whitespace, you might use something like
sed 's/^ //' <<____HERE
Th...