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Why does using an Underscore character in a LIKE filter give me all the results?
... characters. Here you define the escape character with the escape keyword. For details see this link on Oracle Docs.
The '_' and '%' are wildcards in a LIKE operated statement in SQL.
The _ character looks for a presence of (any) one single character. If you search by columnName LIKE '_abc', it wi...
Elegant ways to support equivalence (“equality”) in Python classes
... == n2 # False -- oops
So, Python by default uses the object identifiers for comparison operations:
id(n1) # 140400634555856
id(n2) # 140400634555920
Overriding the __eq__ function seems to solve the problem:
def __eq__(self, other):
"""Overrides the default implementation"""
if isinst...
Regular expression for letters, numbers and - _
...',
'screen-new-file.css',
'screen_new.js',
'screen new file.css'
);
foreach ($arr as $s) {
if (preg_match('/^[\w.-]*$/', $s)) {
print "$s is a match\n";
} else {
print "$s is NO match!!!\n";
};
}
?>
The above prints (as seen on ideone.com):
screen123.css is a match
screen...
Removing multiple keys from a dictionary safely
...c')
the_dict = {'b': 'foo'}
def entries_to_remove(entries, the_dict):
for key in entries:
if key in the_dict:
del the_dict[key]
A more compact version was provided by mattbornski using dict.pop()
s...
namedtuple and default values for optional keyword arguments
...Node' = None
>>> Node()
Node(val=None, left=None, right=None)
Before Python 3.7
Set Node.__new__.__defaults__ to the default values.
>>> from collections import namedtuple
>>> Node = namedtuple('Node', 'val left right')
>>> Node.__new__.__defaults__ = (None,) ...
lodash multi-column sortBy descending
...[true, false]);
Since version 3.10.0 you can even use standard semantics for ordering (asc, desc):
var data = _.sortByOrder(array_of_objects, ['type','name'], ['asc', 'desc']);
In version 4 of lodash this method has been renamed orderBy:
var data = _.orderBy(array_of_objects, ['type','name'], ...
What is the best way to implement nested dictionaries?
...ns county', 'salesmen'): 36}
Here's our usage code:
vividict = Vividict()
for (state, county, occupation), number in data.items():
vividict[state][county][occupation] = number
And now:
>>> import pprint
>>> pprint.pprint(vividict, width=40)
{'new jersey': {'mercer county': {'...
How to determine the version of the C++ standard used by the compiler?
...here is no overall way to do this. If you look at the headers of cross platform/multiple compiler supporting libraries you'll always find a lot of defines that use compiler specific constructs to determine such things:
/*Define Microsoft Visual C++ .NET (32-bit) compiler */
#if (defined(_M_IX86) &a...
Default filter in Django admin
... ('all', _('All')),
)
def choices(self, cl):
for lookup, title in self.lookup_choices:
yield {
'selected': self.value() == lookup,
'query_string': cl.get_query_string({
self.parameter_name: lookup,
...
Elegant setup of Python logging in Django
...rse add handlers to any other loggers too, but there isn't commonly a need for this in my experience.
In each module, I define a logger using
logger = logging.getLogger(__name__)
and use that for logging events in the module (and, if I want to differentiate further) use a logger which is a child...