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Replace all 0 values to NA
...ays in ?'NULL',
NULL represents the null object in R
which is unique and, I guess, can be seen as the most uninformative and empty object.1 Then it becomes not so surprising that
data.frame(x = c(1, NULL, 2))
# x
# 1 1
# 2 2
That is, R does not reserve any space for this null object.2 Mea...
Fast Linux File Count for a large number of files
...lot of them. Also there will be no output until all of the names are read and sorted. Use the ls -f option to turn off sorting.
ls -f | wc -l
Note that this will also enable -a, so ., .., and other files starting with . will be counted.
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Is there a ceiling equivalent of // operator in Python?
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There is no operator which divides with ceil. You need to import math and use math.ceil
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Why do people put code like “throw 1; ” and “for(;;);” in front of json responses? [du
...ased on altering the behaviour of the built-in types, in particular Object and Array, by altering their constructor function or its prototype. Then when the targeted JSON uses a {...} or [...] construct, they'll be the attacker's own versions of those objects, with potentially-unexpected behaviour.
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Local and global temporary tables in SQL Server
What is the difference between local and global temporary tables in SQL Server?
7 Answers
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HTML table with fixed headers?
...isplay a long HTML table such that the column headers stay fixed on-screen and do not scroll with the table body. Think of the "freeze panes" effect in Microsoft Excel.
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Linux error while loading shared libraries: cannot open shared object file: No such file or director
... no libpthread_rt.so.1 in that listing. You probably need to re-configure and re-build it so that it depends on the library you have, or install whatever provides libpthread_rt.so.1.
Generally, the numbers after the .so are version numbers, and you'll often find that they are symlinks to each othe...
CSS center text (horizontally and vertically) inside a div block
I have a div set to display:block ( 90px height and width ), and I have some text inside.
27 Answers
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WebSockets protocol vs HTTP
There are many blogs and discussions about websocket and HTTP, and many developers and sites strongly advocate websockets, but i still can not understand why.
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Circle-Rectangle collision detection (intersection)
How can I tell whether a circle and a rectangle intersect in 2D Euclidean space? (i.e. classic 2D geometry)
25 Answers
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