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php is null or empty?
...LL) {...}
Note the ===.
When use ==, as you did, PHP treats NULL, false, 0, the empty string, and empty arrays as equal.
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What is a regular expression for a MAC Address?
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The standard (IEEE 802) format for
printing MAC-48 addresses in
human-friendly form is six groups of
two hexadecimal digits, separated by
hyphens - or colons :.
So:
^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$
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Pandas dataframe get first row of each group
...column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 second
4 5 first
5 6 first
6 7 fourth
To get n first records, you can use head():
>>> df.groupby('id').head(2).reset_index(drop=True)
id value
0 ...
How to fix the uninitialized constant Rake::DSL problem on Heroku?
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205
Put this in your Rakefile above require 'rake':
require 'rake/dsl_definition'
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Principal component analysis in Python
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edited Sep 3 '10 at 11:40
nikow
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answe...
Is there an equivalent to e.PageX position for 'touchstart' event as there is for click event?
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180
Kinda late, but you need to access the original event, not the jQuery massaged one. Also, since...
How can I autoplay a video using the new embed code style for Youtube?
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+50
Just put "?autoplay=1" in the url the video will autoload.
So your url would be:
http://www.youtube.com/embed/JW5meKfy3fY?autoplay=1
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how to rotate a bitmap 90 degrees
There is a statement in android canvas.drawBitmap(visiblePage, 0, 0, paint);
10 Answers
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Can dplyr package be used for conditional mutating?
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220
Use ifelse
df %>%
mutate(g = ifelse(a == 2 | a == 5 | a == 7 | (a == 1 & b == 4), 2,
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How can I scale an image in a CSS sprite
... not all http://caniuse.com/#search=background-size)
background-size : 150% 150%;
Or
You can use a combo of zoom for webkit/ie and transform:scale for Firefox(-moz-) and Opera(-o-) for cross-browser desktop & mobile
[class^="icon-"]{
display: inline-block;
background: url('../img/...