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Preferred method to store PHP arrays (json_encode vs serialize)
...() you need to add extra parameter to keep UTF-8 characters untouched: json_encode($array, JSON_UNESCAPED_UNICODE) (otherwise it converts UTF-8 characters to Unicode escape sequences).
JSON will have no memory of what the object's original class was (they are always restored as instances of stdClas...
mongodb: insert if not exists
... This is almost what I want ! How can I not touch the insertion_date field if the object is already present ?
– LeMiz
May 27 '10 at 21:24
28
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Calling shell functions with xargs
...
Exporting the function should do it (untested):
export -f echo_var
seq -f "n%04g" 1 100 | xargs -n 1 -P 10 -I {} bash -c 'echo_var "$@"' _ {}
You can use the builtin printf instead of the external seq:
printf "n%04g\n" {1..100} | xargs -n 1 -P 10 -I {} bash -c 'echo_var "$@"' _ {}
...
Naming convention for unique constraint
...primary key and foreign key have commonly used and obvious conventions ( PK_Table and FK_Table_ReferencedTable , respectively). The IX_Table_Column naming for indexes is also fairly standard.
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Does SQLAlchemy have an equivalent of Django's get_or_create?
...ortcut readily available AFAIK.
You could generalize it ofcourse:
def get_or_create(session, model, defaults=None, **kwargs):
instance = session.query(model).filter_by(**kwargs).first()
if instance:
return instance, False
else:
params = dict((k, v) for k, v in kwargs.it...
Make absolute positioned div expand parent div height
...ld1 and child2 in relative divs with display:none in parent div. Say child1_1 and child2_2. Put child2_2 on top and child1_1 at the bottom.
When your jquery (or whatever) calls the absolute div, just set the according relative div (child1_1 or child2_2) with display:block AND visibility:hidden. The...
Python memory usage of numpy arrays
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b.__sizeof__() is equivalent to sys.getsizeof(b)
– palash
Feb 27 at 7:02
1
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Rails :include vs. :joins
... what I understood (with examples :))
Consider this scenario:
A User has_many comments and a comment belongs_to a User.
The User model has the following attributes: Name(string), Age(integer). The Comment model has the following attributes:Content, user_id. For a comment a user_id can be null.
...
Getting a random value from a JavaScript array
...u've already got underscore or lodash included in your project you can use _.sample.
// will return one item randomly from the array
_.sample(['January', 'February', 'March']);
If you need to get more than one item randomly, you can pass that as a second argument in underscore:
// will return tw...
Storing time-series data, relational or non?
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Create a file, name it 1_2.data. weired idea? what you get:
You save up to 50% of space because you don't need to repeat the fk_to_device and fk_to_metric value for every data point.
You save up even more space because you don't need any indices.
...