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React.js - input losing focus when rerendering
...h="/user" render={() => <UserPage/>} />
The loss of focus happens because the component prop uses React.createElement each time instead of just re-rendering the changes.
Details here: https://reacttraining.com/react-router/web/api/Route/component
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Sending multipart/formdata with jQuery.ajax
...how is it possible to send this Data to the server? The resulting array ( $_POST ) on the serverside php-script is 0 ( NULL ) when using the file-input.
...
What are the applications of binary trees?
...oving from one level to the next requires one comparison, and there are log_2(m) levels, for a total of log_2(m) comparisons.
In contrast, an n-ary tree will require log_2(n) comparisons (using a binary search) to move to the next level. Since there are log_n(m) total levels, the search will requi...
How do I expire a PHP session after 30 minutes?
...a session timeout of your own. Both options mentioned by others (session.gc_maxlifetime and session.cookie_lifetime) are not reliable. I'll explain the reasons for that.
First:
session.gc_maxlifetime
session.gc_maxlifetime specifies the number of seconds after which data will be seen as 'garb...
Why do you need explicitly have the “self” argument in a Python method?
...hing is implied or assumed, parts of the implementation are exposed. self.__class__, self.__dict__ and other "internal" structures are available in an obvious way.
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How can I rename a field for all documents in MongoDB?
...ormer way:
remap = function (x) {
if (x.additional){
db.foo.update({_id:x._id}, {$set:{"name.last":x.name.additional}, $unset:{"name.additional":1}});
}
}
db.foo.find().forEach(remap);
In MongoDB 3.2 you can also use
db.students.updateMany( {}, { $rename: { "oldname": "newname" } } )
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What does the Q_OBJECT macro do? Why do all Qt objects need this macro?
...ing Qt and noticed that all the example class definitions have the macro Q_OBJECT as the first line. What is the purpose of this preprocessor macro?
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How do I diff the same file between two different commits on the same branch?
...fferent files in two different revisions, like this:
git diff <revision_1>:<file_1> <revision_2>:<file_2>
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Can PostgreSQL index array columns?
...0}');
INSERT INTO "Test" VALUES ('{10, 20, 30}');
CREATE INDEX idx_test on "Test" USING GIN ("Column1");
-- To enforce index usage because we have only 2 records for this test...
SET enable_seqscan TO off;
EXPLAIN ANALYZE
SELECT * FROM "Test" WHERE "Column1" @> ARRAY[2...
How to print a dictionary line by line in Python?
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I do print(json.dumps(cars, indent=4, ensure_ascii=False)) because otherwise non-ASCII characters are unreadable.
– Boris
Apr 22 at 16:36
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