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Scala how can I count the number of occurrences in a list
...-> 3, apple -> 3)
The question asks how to find the count of a specific item. With this approach, the solution would require mapping the desired element to its count value as follows:
s.groupBy(identity).mapValues(_.size)("apple")
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MySql Table Insert if not exist otherwise update
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now I defined the datenum as unique, and it's work fine, thanks
– OHLÁLÁ
May 18 '11 at 8:21
1
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private[this] vs private
... learnt to close everything (make it private) and open (provide accessors) if necessary. Scala introduces even more strict access modifier. Should I always use it by default? Or should I use it only in some specific cases where I need to explicitly restrict changing field value even for objects of t...
CSS3 transition events
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Is there now a standard way of achieving this? Seems 2 years is a long time! Things have likely changed.
– Mild Fuzz
May 22 '12 at 15:52
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Django select only rows with duplicate field values
...viously had a bug on this (might have been fixed in recent versions) where if you don't specify a fieldname for the Count annotation to saved as, it defaults to [field]__count. However, that double-underscore syntax is also how Django interprets you wanting to do a join. So, essentially when you try...
What does T&& (double ampersand) mean in C++11?
...bs Jul 13 '14 at 16:12
The biggest difference between a C++03 reference (now called an lvalue reference in C++11) is that it can bind to an rvalue like a temporary without having to be const. Thus, this syntax is now legal:
T&& r = T();
rvalue references primarily provide for the follo...
Pragma in define macro
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If you're using c99 or c++0x there is the pragma operator, used as
_Pragma("argument")
which is equivalent to
#pragma argument
except it can be used in macros (see section 6.10.9 of the c99 standard, or 16.9 of the c++0...
“Debug certificate expired” error in Eclipse Android plugins
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There is now a bug tracker issue requesting this to be fixed. Please vote for it. code.google.com/p/android/issues/detail?id=15370
– Manfred Moser
Mar 9 '11 at 19:52
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Get ffmpeg information in friendly way
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Now is possible to use -progress - to print friendly info formatted by key=value.
ffmpeg -i video.mp4 .......-s 1920x1080 -progress - -y out.mp4
speed=5.75x
frame=697
fps=167.7
stream_0_0_q=39.0
bitrate=2337.0kbits/s
total...
How to git-cherry-pick only changes to certain files?
...tively with git reset -p HEAD. It's the equivalent of add -p but very few know that it exists.
– Patrick Schlüter
Mar 14 '17 at 9:09
2
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