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SQL: How to properly check if a record exists
...optimize SELECT COUNT(*) anyway, so while there is a difference in theory (and older databases), you shouldn't notice any difference in practice.
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how do i block or restrict special characters from input fields with jquery?
...l allowed for the use of control characters (e.g., backspace, delete, tab) and copy+paste. None of the provided answers that I tried satisfied all of these requirements, so I came up with the following using the input event.
$('input').on('input', function() {
$(this).val($(this).val().replace(/[...
angularjs directive call function specified in attribute and pass an argument to it
...o use a callback expression which does not require defining the expressionHandler. In marko's example change:
In template
<div my-method="theMethodToBeCalled(myParam)"></div>
In directive link function
$(element).click(function( e, rowid ) {
scope.method({myParam: id});
});
This...
Django Admin - Disable the 'Add' action for a specific model
I have a django site with lots of models and forms. I have many custom forms and formsets and inlineformsets and custom validation and custom querysets. Hence the add model action depends on forms that need other things, and the 'add model' in the django admin throughs a 500 from a custom queryset.
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Test whether a list contains a specific value in Clojure
...se for sets (which can be thought of as making no distinction between keys and values), maps (so (contains? {:foo 1} :foo) is true) and vectors (but note that (contains? [:foo :bar] 0) is true, because the keys here are indices and the vector in question does "contain" the index 0!).
To add to the ...
Get distance between two points in canvas
I have canvas drawing tab and want lineWidth to be based on distance between two last mousemove coordinate updates. I will make translation of distance to width myself, I just need to know how to get distance between those points (I already have coordinates of those pointes).
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On select change, get data attribute value
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I've just come across this and I am wondering if the first method is preferred due to performance reasons, or another reason? @JordanBrown
– Clarkey
Aug 19 '15 at 15:31
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How can I remove an element from a list?
I have a list and I want to remove a single element from it. How can I do this?
16 Answers
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How to specify a multi-line shell variable?
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set -e exits the shell if a command has an "unanticipated" non-zero exit status. By "unanticipated", I mean it runs in a context where you aren't specifically looking at its exit status. false by itself, for instance, would exit the shell. false || true wou...
Disable submit button when form invalid with AngularJS
...form/> tag, if for no other reason than it allows a user to hit [ENTER] and submit the form. But it also likely constitutes better practice because of things like accessibility concerns.
– Ben Lesh
Nov 13 '14 at 20:14
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