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How do you round a floating point number in Perl?
...f perldoc -q round
Does Perl have a round() function? What about ceil() and floor()?
Trig functions?
Remember that int() merely truncates toward 0. For rounding to a certain number of digits, sprintf() or printf() is usually the easiest
route.
printf("%.3f", 3.1415926535); # prints 3...
pandas read_csv and filter columns with usecols
I have a csv file which isn't coming in correctly with pandas.read_csv when I filter the columns with usecols and use multiple indexes.
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How many threads is too many?
I am writing a server, and I send each action of into a separate thread when the request is received. I do this because almost every request makes a database query. I am using a threadpool library to cut down on construction/destruction of threads.
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How do you change the size of figures drawn with matplotlib?
...figsize=(8, 6), ...) to change it's size etc. If you're using pyplot/pylab and show() to create a popup window, you need to call figure(num=1,...) before you plot anything - pyplot/pylab creates a figure as soon as you draw something, and the size of the popup appears to be fixed at this point.
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Python to print out status bar and percentage
...character (carriage return) resets the cursor to the beginning of the line and allows you to write over what was previously on the line.
from time import sleep
import sys
for i in range(21):
sys.stdout.write('\r')
# the exact output you're looking for:
sys.stdout.write("[%-20s] %d%%" %...
How to center align the cells of a UICollectionView?
I am currently using UICollectionView for the user interface grid, and it works fine. However, I'd like to be enable horizontal scrolling. The grid supports 8 items per page and when the total number of items are, say 4, this is how the items should be arranged with horizontal scroll direction ena...
Extract month and year from a zoo::yearmon object
... "%m"))
[1] 3
> as.numeric(format(date1, "%Y"))
[1] 2012
See ?yearmon and ?strftime for details - the latter explains the placeholder characters you can use.
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How to get users to read error messages?
...ind yourself at a high risk that users will not read your carefully worded and enlightening error messages, but just click on the first button available with a shrug of frustration.
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Returning null as an int permitted with ternary operator but not if statement
...itional operator (as described in the Java Language Specification, 15.25), and moves happily on. This will generate a NullPointerException at run time, which you can confirm by trying it.
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Android and in TextView
...review in XML) nor by setting them in Java with setText(). Tried both with Android 4.1 and 4.2
– Stephan Wiesner
Feb 20 '13 at 6:08
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