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How do I check for null values in JavaScript?
... will check for empty strings (""), null, undefined, false and the numbers 0 and NaN
Please note that if you are specifically checking for numbers it is a common mistake to miss 0 with this method, and num !== 0 is preferred (or num !== -1 or ~num (hacky code that also checks against -1)) for funct...
How can I convert the “arguments” object to an array in JavaScript?
...
730
+100
ES6 usin...
Anonymous recursive PHP functions
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answered Mar 19 '10 at 20:03
Derek HDerek H
10.2k66 gold badges3232 silver badges3838 bronze badges
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Get all child views inside LinearLayout at once
...earLayout ll = …
final int childCount = ll.getChildCount();
for (int i = 0; i < childCount; i++) {
View v = ll.getChildAt(i);
// Do something with v.
// …
}
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Password masking console application
...Info.Key;
if (key == ConsoleKey.Backspace && pass.Length > 0)
{
Console.Write("\b \b");
pass = pass[0..^1];
}
else if (!char.IsControl(keyInfo.KeyChar))
{
Console.Write("*");
pass += keyInfo.KeyChar;
}
} while (key != ConsoleKey.Ent...
Python argparse: default value or specified value
...example=1)
% test.py --example 2
Namespace(example=2)
nargs='?' means 0-or-1 arguments
const=1 sets the default when there are 0 arguments
type=int converts the argument to int
If you want test.py to set example to 1 even if no --example is specified, then include default=1. That is, with
...
How can I extract a good quality JPEG image from a video file with ffmpeg?
...2).
To output a series of images:
ffmpeg -i input.mp4 -qscale:v 2 output_%03d.jpg
See the image muxer documentation for more options involving image outputs.
To output a single image at ~60 seconds duration:
ffmpeg -ss 60 -i input.mp4 -qscale:v 4 -frames:v 1 output.jpg
This will work with any vid...
Generate random 5 characters string
...
$rand = substr(md5(microtime()),rand(0,26),5);
Would be my best guess--Unless you're looking for special characters, too:
$seed = str_split('abcdefghijklmnopqrstuvwxyz'
.'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
.'0123456789!@#$%^&*()...
Show an image preview before upload
... // read the image file as a data URL.
reader.readAsDataURL(this.files[0]);
};
Here's a good article on using the File APIs in JavaScript.
The code snippet in the HTML example below filters out images from the user's selection and renders selected files into multiple thumbnail previews:
...
How to set enum to null
...e for enums that cannot be null by having the FIRST value in the enum (aka 0) be the default value. For example in a case of color None.
public Color myColor = Color.None;
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