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What is the Ruby (spaceship) operator?
...en return -1
if a = b then return 0
if a > b then return 1
if a and b are not comparable then return nil
It's useful for sorting an array.
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Which characters are valid in CSS class names/selectors?
...racter is a hyphen, the second character must2 be a letter or underscore, and the name must be at least 2 characters long.
-?[_a-zA-Z]+[_a-zA-Z0-9-]*
In short, the previous rule translates to the following, extracted from the W3C spec.:
In CSS, identifiers (including element names, classes, ...
The application may be doing too much work on its main thread
I am new to Android SDK/API environment. It's the first I am trying to draw a plot/chart. I tried running different kinds of sample codes the emulator using 3 different free libraries, nothing is showing in the layout screen. The logcat is repeating the following message:
...
Can someone give an example of cosine similarity, in a very simple, graphical way?
... want to know how similar these texts are, purely in terms of word counts (and ignoring word order). We begin by making a list of the words from both texts:
me Julie loves Linda than more likes Jane
Now we count the number of times each of these words appears in each text:
me 2 2
Jane ...
How to tell if a string is not defined in a Bash shell script
...Autoconf, you'll find that they do not recommend combining terms with '-a' and do recommend using separate simple tests combined with &&. I've not encountered a system where there is a problem; that doesn't mean they didn't used to exist (but they are probably extremely rare these days, eve...
What is a “surrogate pair” in Java?
...mething about surrogate pairs . What is a surrogate pair in this context? And what are low and high surrogates?
7 An...
Using OR in SQLAlchemy
I've looked through the docs and I cant seem to find out how to do an OR query in SQLAlchemy. I just want to do this query.
...
Does MS SQL Server's “between” include the range boundaries?
...t_expression is greater than or
equal to the value of begin_expression
and less than or equal to the value of
end_expression.
DateTime Caveat
NB: With DateTimes you have to be careful; if only a date is given the value is taken as of midnight on that day; to avoid missing times within your ...
How to randomize (or permute) a dataframe rowwise and columnwise?
...,]
> df2
a b c
3 0 1 0
4 0 0 0
2 1 0 0
1 1 1 0
By default sample() randomly reorders the elements passed as the first argument. This means that the default size is the size of the passed array. Passing parameter replace=FALSE (the default) to sample(...) ensures that sampling is done withou...
SHA1 vs md5 vs SHA256: which to use for a PHP login?
I'm making a php login, and I'm trying to decide whether to use SHA1 or Md5, or SHA256 which I read about in another stackoverflow article. Are any of them more secure than others? For SHA1/256, do I still use a salt?
...