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Pandas count(distinct) equivalent
...This is the incorrect answer; it does not reflect the DISTINCT requirement from the question! Moreover, it does not include counts of NaN!
– Corey Levinson
Jan 23 '19 at 20:03
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Are Databases and Functional Programming at odds?
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Coming at this from the perspective of a database person, I find that front end developers try too hard to find ways to make databases fit their model rather than consider the most effective ways to use database which are not object oriente...
python multithreading wait till all threads finished
...roceed to wait for t3). If t1 took the longest to execute, when you return from it both t1 and t2 will return immediately without blocking.
– Maksim Skurydzin
Aug 15 '12 at 12:06
1...
JUnit: how to avoid “no runnable methods” in test utils classes
I have switched to JUnit4.4 from JUnit3.8. I run my tests using ant, all my tests run successfully but test utility classes fail with "No runnable methods" error. The pattern I am using is to include all classes with name *Test* under test folder.
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Why is it common to put CSRF prevention tokens in cookies?
... the same user account as the victim's auth session cookie will be missing from the request (it would be the attacker's - therefore it won't be associated server side with the victim's session).
As well as the Synchronizer Token Pattern there is also the Double Submit Cookie CSRF prevention method,...
How to prevent http file caching in Apache httpd (MAMP)
...a VirtualHost (usually placed in httpd-vhosts.conf if you have included it from your httpd.conf)
<filesMatch "\.(html|htm|js|css)$">
FileETag None
<ifModule mod_headers.c>
Header unset ETag
Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
Heade...
How to read/write a boolean when implementing the Parcelable interface?
...e((byte) (myBoolean ? 1 : 0)); //if myBoolean == true, byte == 1
readFromParcel:
myBoolean = in.readByte() != 0; //myBoolean == true if byte != 0
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How to convert a string of numbers to an array of numbers?
...ad of 6)) is equivalent to :
function(x){return parseInt(x,10)}// version from techfoobar
(x)=>{return parseInt(x)} // lambda are shorter and parseInt default is 10
(x)=>{return +x} // diff. with parseInt in SO but + is better in this case
x=>+x ...
How to check whether an object is a date?
....prototype, which is the reason for the instanceof failure: Date.prototype from frame1 is not part of the prototype chain of Date instances from frame2
– Christoph
Apr 13 '10 at 16:25
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wkhtmltopdf: cannot connect to X server
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or try this (from http://drupal.org/node/870058)
Download wkhtmltopdf. Or better install it with a package manager:
sudo apt-get install wkhtmltopdf
Extract it and move it to /usr/local/bin/
Rename it to wkhtmltopdf so that now you ha...