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An item with the same key has already been added
...this error whenever I submit the form also the action method is not being called because of this:
21 Answers
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How can I convert a string to a number in Perl?
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You don't need to convert it at all:
% perl -e 'print "5.45" + 0.1;'
5.55
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What's the maximum value for an int in PHP?
Ignoring the special libraries that allow you to work with very big numbers, what's the largest int value you can store in PHP?
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How to trigger a file download when clicking an HTML button or JavaScript
...Edge) and it is not supported in Safari. In 2012 when the answer was originally posted it wasn't supported in any major browser.
– Cfreak
Jul 7 '16 at 3:40
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Vibrate and Sound defaults on notification
...gb format, like 0xffffffff, instead of Color.White, because there's is a small chance of user device use Color(RGB) for a ARGB param and you will get the wrong color. This Happened with me.
– Beto Caldas
Oct 24 '14 at 19:47
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Convert Pandas column containing NaNs to dtype `int`
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@jsc123 you can use the object dtype. This comes with a small health warning but for the most part works well.
– Andy Hayden
May 19 '15 at 15:16
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What does !! mean in ruby?
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!!nil #=> false
!!"abc" #=> true
!!false #=> false
It's usually not necessary to use though since the only false values to Ruby are nil and false, so it's usually best to let that convention stand.
Think of it as
!(!some_val)
One thing that is it used for legitimately is preventi...
What's the difference between & and && in MATLAB?
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@neuronet it isn't really about efficiency, more that it permits a construct where the first expression guarantees a condition without which the second expression may cause a run-time error. e.g. d != 0 && 1/d vs d !=0 & 1/d - the ...
Can an int be null in Java?
... @BrianAgnew Let me rectify what I said here, I was plain wrong, I basically didn't realize that int i = (Integer)null; will throw NPE at run-time while unboxing it.
– sactiw
Jan 23 '16 at 12:22
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How to take backup of a single table in a MySQL database?
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SQL usually compresses well--you can pipe the command above through gzip and the resulting file will be much smaller: mysqldump db_name table_name | gzip > table_name.sql.gz to restore: gunzip < table_name.sql.gz | mysql -u...