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In Scala, what exactly does 'val a: A = _' (underscore) mean?
....0d if T is Double,
false if T is Boolean,
() if T is Unit,
null for all other types T.
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find vs find_by vs where
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Use whichever one you feel suits your needs best.
The find method is usually used to retrieve a row by ID:
Model.find(1)
It's worth noting that find will throw an exception if the item is not found by the attribute that you supply. Use where (as described below, which will return an empty arr...
How to combine two or more querysets in a Django view?
...sets into a list is the simplest approach. If the database will be hit for all querysets anyway (e.g. because the result needs to be sorted), this won't add further cost.
from itertools import chain
result_list = list(chain(page_list, article_list, post_list))
Using itertools.chain is faster than...
Is there a setting on Google Analytics to suppress use of cookies for users who have not yet given c
... implement a mechanism where, on first visit, Google Analytics is automatically disabled in the absence of an opt-in cookie (cookies that determine cookie preferences are explicitly allowed), and then, if an opt-in happens, re-runs Google Analytics. On subsequent pageviews, all would run smoothly.
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Read properties file outside JAR file
I have a JAR file where all my code is archived for running. I have to access a properties file which need to be changed/edited before each run. I want to keep the properties file in the same directory where the JAR file is. Is there anyway to tell Java to pick up the properties file from that direc...
How can I get all the request headers in Django?
I need to get all the Django request headers. From what i've read, Django simply dumps everything into the request.META variable along with a lot aof other data. What would be the best way to get all the headers that the client sent to my Django application?
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Can anyone explain python's relative imports?
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Thanks, but this honestly seems really silly. For such a beautiful language, I can't believe the designers would create such a restriction. Isn't there any other way?
– carl
Dec 16 '09 at 23:48
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How can I add a key/value pair to a JavaScript object?
... property. The second form is used when the name of the property is dynamically determined. Like in this example:
var getProperty = function (propertyName) {
return obj[propertyName];
};
getProperty("key1");
getProperty("key2");
getProperty("key3");
A real JavaScript array can be construct...
Where do “pure virtual function call” crashes come from?
...programs that crash on my computer with the error: "pure virtual function call".
8 Answers
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How to ALTER multiple columns at once in SQL Server
.... Each statement means a new scan but if you could alter multiple columns, all altering could have been much quicker
– erikkallen
Sep 8 '16 at 6:31
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