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JavaScript null check
... confusing in JavaScript. However, it's always safe to test if the typeof(x) is the string "undefined", even if "x" is not a declared variable:
alert(typeof(x) === 'undefined'); // true
Also, variables can have the "undefined value" if they are not initialized:
var y;
alert(typeof(y) === 'undef...
When to use ' (or quote) in Lisp?
...
Short answer
Bypass the default evaluation rules and do not evaluate the expression (symbol or s-exp), passing it along to the function exactly as typed.
Long Answer: The Default Evaluation Rule
When a regular (I'll come to that later) function is invoked, all arguments passed to it are evaluated...
How can I send an HTTP POST request to a server from Excel using VBA?
What VBA code is required to perform an HTTP POST from an Excel spreadsheet?
6 Answers
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Height of status bar in Android [duplicate]
...method:
ok, the height of the status bar depends on the screen size, for example in a device
with 240 X 320 screen size the status bar height is 20px, for a device with 320 X 480 screen size the status bar height is 25px, for a device with 480 x 800 the status bar height must be 38px
so i recomme...
When should the xlsm or xlsb formats be used?
Since Excel 2007, Microsoft has split the classical .xls format to several formats (in particular, .xlsx , .xlsm , .xlsb ). I've got no problem to understand the use and purpose of .xlsx format but I am still wondering whether we should use a .xlsm or a .xlsb format when creating a file c...
Why is it common to put CSRF prevention tokens in cookies?
...hout the application in client script for use in both regular forms and AJAX POSTs. This will make sense in a JavaScript heavy application such as one employed by AngularJS (using AngularJS doesn't require that the application will be a single page app, so it would be useful where state needs to flo...
Difference between LoadFile and LoadFrom with .NET Assemblies?
...ooking at the msdn documentation and I am still a little confused on what exactly is the difference between using LoadFile and LoadFrom when loading an assembly. Can someone provide an example or an analogy to better describe it. The MSDN documentation confused me more. Also, Is ReflectionOnlyL...
How to dynamically create a class?
...ection.Emit namespace for this. It is not straight forward if you have no experience with it, but it is certainly possible.
Edit: This code might be flawed, but it will give you the general idea and hopefully off to a good start towards the goal.
using System;
using System.Reflection;
using System...
PostgreSQL array_agg order
...g the input values from a sorted subquery will usually work, however. For example:
SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
So in your case you would write:
SELECT
array_to_string(array_agg(animal_name),';') animal_names,
array_to_string(array_agg(animal_type),';') ...
Why does (1 in [1,0] == True) evaluate to False?
...
Python actually applies comparison operator chaining here. The expression is translated to
(1 in [1, 0]) and ([1, 0] == True)
which is obviously False.
This also happens for expressions like
a < b < c
which translate to
(a < b) and (b < c)
(without evaluating b twice...