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The modulo operation on negative numbers in Python
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Here's an explanation from Guido van Rossum:
http://python-history.blogspot.com/2010/08/why-pythons-integer-division-floors.html
Essentially, it's so that a/b = q with remainder r preserves the relationships b*q + r = a and 0 <= r < b.
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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
...ime, especially since your data are already factored, you can use complete from "tidyr" to get what you might be looking for:
library(tidyr)
df %>%
group_by(b) %>%
summarise(count_a=length(a)) %>%
complete(b)
# Source: local data frame [3 x 2]
#
# b count_a
# (fctr) (int)...
Undo scaffolding in Rails
... In some cases there are still leftover files that were not deleted from the scaffold. Check your version control, e.g. git status and/or git diff, to see if the destroy command missed anything.
– aaron-coding
Mar 31 '15 at 21:58
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What does LINQ return when the results are empty
...!YourResult.Any())
Just a note that .Any will still retrieve the records from the database; doing a .FirstOrDefault()/.Where() will be just as much overhead but you would then be able to catch the object(s) returned from the query
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newline in [duplicate]
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using this from jquery it appears to want the real value not the encoded one, as I think it encodes for you. I used \r
– Maslow
Mar 21 '14 at 17:14
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Substitute multiple whitespace with single whitespace in Python [duplicate]
...on as asked (the unexpressed intent of the question of course might differ from the very explicit expression of it, but, mind-reading is not a very widespread skill:-).
– Alex Martelli
Aug 28 '15 at 21:45
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What jsf component can render a div tag?
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Apart from the <h:panelGroup> component (which comes as a bit of a surprise to me), you could use a <f:verbatim> tag with the escape parameter set to false to generate any mark-up you want. For example:
<f:verbatim ...
How do I enlarge an EER Diagram in MySQL Workbench?
... Model > Model Options;
Choose the "Diagram" tab;
Uncheck "Use defaults from global settings..." at the bottom;
Confirm "Ok". This may crash Workbench, depending on the version and/or operating system.
Either way, "Model > Diagram Properties and Size..." should now be enabled, even if you had...
What does auto do in margin:0 auto?
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From the CSS specification on Calculating widths and margins for Block-level, non-replaced elements in normal flow:
If both 'margin-left' and 'margin-right' are 'auto', their used values are equal. This horizontally cente...
Multiple contexts with the same path error running web service in Eclipse using Tomcat
... tag may be on the same line, but outside the viewport and really far away from the visible one.
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