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Check whether a value is a number in JavaScript or jQuery [duplicate]
...ic string with trailing letters the parseFloat | parseInt will return true and the second check isFInite will return false. While with unary + it will fail immediately.
– Arman McHitarian
May 20 '13 at 16:29
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What is the difference between a weak reference and an unowned reference?
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Both weak and unowned references do not create a strong hold on the referred object (a.k.a. they don't increase the retain count in order to prevent ARC from deallocating the referred object).
But why two keywords? This distinction has...
What is the difference between SAX and DOM?
I read some articles about the XML parsers and came across SAX and DOM .
10 Answers
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How to rollback a specific migration?
...STEP=5
Will also rollback all the migration that happened later (4, 3, 2 and also 1).
To roll back all migrations back to (and including) a target migration, use: (This corrected command was added AFTER all the comments pointing out the error in the original post)
rake db:migrate VERSION=2010090...
How do I negate a condition in PowerShell?
...ld also use bitwise exclusive or, though it's not the most readable/understandable method.
if ((test-path C:\code) -bxor 1) {write "it doesn't exist!"}
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How can I format my grep output to show line numbers at the end of the line, and also the hit count?
...two null, - Line number : 2
example four null, - Line number : 4
Use command substitution to print out the total null count:
$ echo "Total null count :" $(grep -ic null myfile.txt)
Total null count : 2
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MySQL: Set user variable from result of query
...rator. However inside other statements, the assignment operator must be := and not = because = is treated as a comparison operator in non-SET statements.
UPDATE:
Further to comments below, you may also do the following:
SET @user := 123456;
SELECT `group` FROM user LIMIT 1 INTO @group;
SELECT ...
How to access the correct `this` inside a callback?
I have a constructor function which registers an event handler:
11 Answers
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Position icons into circle
...can I position several <img> elements into a circle around another and have those elements all be clickable links as well? I want it to look like the picture below, but I have no idea how to achieve that effect.
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How to Sign an Already Compiled Apk
...ssues with the layout xml files. I've then rebuilt it back up with apktool and when I tried to install it on my device (using adb: adb install appname.apk) it gave me this error:
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