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How to sum a variable by group
...ow to summarise data by group using dplyr functions using the built-in dataset mtcars:
# several summary columns with arbitrary names
mtcars %>%
group_by(cyl, gear) %>% # multiple group columns
summarise(max_hp = max(hp), mean_mpg = mean(mpg)) # multiple summa...
Limit text length to n lines using CSS
...r caveats.
The basics are simple, it hides the overflow of the span, and sets the max height based on the line height as suggested by Eugene Xa.
Then there is a pseudo class after the containing div that places the ellipsis nicely.
Caveats
This solution will always place the ellipsis, regardle...
Running SSH Agent when starting Git Bash on Windows
...ion, you can add a script to ~/.profile or ~/.bashrc (with ~ being usually set to %USERPROFILE%), in order for said session to launch automatically the ssh-agent. If the file doesn't exist, just create it.
This is what GitHub describes in "Working with SSH key passphrases".
The "Auto-launching ss...
Uint8Array to string in Javascript
I have some UTF-8 encoded data living in a range of Uint8Array elements in Javascript. Is there an efficient way to decode these out to a regular javascript string (I believe Javascript uses 16 bit Unicode)? I dont want to add one character at the time as the string concaternation would become to CP...
Mod in Java produces negative numbers [duplicate]
When I calculate int i = -1 % 2 I get -1 in Java. In Python, I get 1 as the result of -1 % 2 .
What do I have to do to get the same behavior in Java with the modulo function?
...
Is there a limit on how much JSON can hold?
...s no inherent size limitation to the JSON request. Any limitation would be set by the server parsing the request. (For instance, ASP.NET has the "MaxJsonLength" property of the serializer.)
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serve current directory from command line
...eeted it out today you can do:
ruby -run -e httpd . -p 5000
And you can set the bind address as well by adding -b 127.0.0.1
Works with Ruby 1.9.2 and greater.
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What's the difference between lapply and do.call?
... editor after snippets, if snippets enabled
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How to call a method defined in an AngularJS directive?
...n't have a control attr will start throwing errors about not being able to set attributes on undefined
– CheapSteaks
Mar 16 '14 at 0:55
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Retrieve list of tasks in a queue in Celery
... DEFAULT_PRIORITY_STEPS]
r = redis.StrictRedis(
host=settings.REDIS_HOST,
port=settings.REDIS_PORT,
db=settings.REDIS_DATABASES['CELERY'],
)
return sum([r.llen(x) for x in priority_names])
If you want to get an actual task, you can use something like:
...