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How do I find the duplicates in a list and create another list with them?
..., 2, 5]
Note that Counter is not particularly efficient (timings) and probably overkill here. set will perform better. This code computes a list of unique elements in the source order:
seen = set()
uniq = []
for x in a:
if x not in seen:
uniq.append(x)
seen.add(x)
or, more c...
How to reorder data.table columns (without copying)
I'd like to reorder columns in my data.table x , given a character vector of column names, neworder :
2 Answers
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How can you set class attributes from variable arguments (kwargs) in python
...se I have a class with a constructor (or other function) that takes a variable number of arguments and then sets them as class attributes conditionally.
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JavaScript variable number of arguments to function
...
Sure, just use the arguments object.
function foo() {
for (var i = 0; i < arguments.length; i++) {
console.log(arguments[i]);
}
}
share
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im...
Is there a Null OutputStream in Java?
I need to specify an OutputStream for an API I'm using, but I don't actually have a need for the output. Does Java have an OutputStream equivalent to > /dev/null ?
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URL encoding in Android
...
You don't encode the entire URL, only parts of it that come from "unreliable sources".
String query = URLEncoder.encode("apples oranges", "utf-8");
String url = "http://stackoverflow.com/search?q=" + query;
Alternatively, you can use Strings.urlEncode(String str) of DroidParts that doesn't thro...
Why did my Git repo enter a detached HEAD state?
I ended up with a detached head today, the same problem as described in: git push says everything up-to-date even though I have local changes
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Regex not operator
...xt following (hence: lookahead) this doesn't (hence: negative) match this. But it doesn't actually consume the characters it matches (hence: zero-width).
There are actually 4 combinations of lookarounds with 2 axes:
lookbehind / lookahead : specifies if the characters before or after the point ar...
How to directly initialize a HashMap (in a literal way)?
...etonMap("key", "value").
For Java Version 9 or higher:
Yes, this is possible now. In Java 9 a couple of factory methods have been added that simplify the creation of maps :
// this works for up to 10 elements:
Map<String, String> test1 = Map.of(
"a", "b",
"c", "d"
);
// this works ...
Difference between a Structure and a Union
Is there any good example to give the difference between a struct and a union ?
Basically I know that struct uses all the memory of its member and union uses the largest members memory space. Is there any other OS level difference?
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