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Select first 4 rows of a data.frame in R
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156
Use head:
dnow <- data.frame(x=rnorm(100), y=runif(100))
head(dnow,4) ## default is 6
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How to match “any character” in regular expression?
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11 Answers
11
Active
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Secondary axis with twinx(): how to add to legend?
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391
You can easily add a second legend by adding the line:
ax2.legend(loc=0)
You'll get this:
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What is the use of the ArraySegment class?
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edited Oct 1 '19 at 22:03
answered Oct 26 '11 at 18:15
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ERROR: Error installing capybara-webkit:
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218
If you are in Ubuntu do
sudo apt-get install qt4-dev-tools libqt4-dev libqt4-core libqt4-gui
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Reload django object from database
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As of Django 1.8 refreshing objects is built in. Link to docs.
def test_update_result(self):
obj = MyModel.objects.create(val=1)
MyModel.objects.filter(pk=obj.pk).update(val=F('val') + 1)
# At this point obj.val is still 1, b...
Bower and devDependencies vs dependencies
I ran 'yo angular' and realized afterwards that it installs 1.0.8, I uninstalled the angular components, however the original bower.json file had angular-mocks and angular-scenario under 'devDependencies' when I re-add all the 1.2.0-rc.2 components angular-mocks and angular-scenario under dependenci...
What is a “callback” in C and how are they implemented?
...RandomValue(void)
{
return rand();
}
int main(void)
{
int myarray[10];
populate_array(myarray, 10, getNextRandomValue);
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}
Here, the populate_array function takes a function pointer as its third parameter, and calls it to get the values to populate the array with. We've written...
How to delete and replace last line in the terminal using bash?
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117
echo a carriage return with \r
seq 1 1000000 | while read i; do echo -en "\r$i"; done
from ...
setup cron tab to specific time of during weekdays
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177
Same as you did for hours:
*/2 09-18 * * 1-5 /path_to_script
0 and 7 stand for Sunday
6 sta...