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How do I determine k when using k-means clustering?
... clear is how you choose the value of k. Is it just a matter of trial and error, or is there more to it?
19 Answers
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leading zeros in rails
...herwise, returns str.
some_int = 5
some_int.to_s.rjust(2, '0') # => '05'
some_int.to_s.rjust(5, '0') # => '00005'
another_int = 150
another_int.to_s.rjust(2, '0') # => '150'
another_int.to_s.rjust(3, '0') # => '150'
another_int.to_s.rjust(5, '0') # => '00150'
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A cron job for rails: best practices?
...).
– aceofbassgreg
Apr 11 '13 at 18:05
@Tony, Whenever is basically a domain specific language for writing cron jobs. ...
C/C++ check if one bit is set in, i.e. int variable
... a std::bitset if it's C++. Simple. Straight-forward. No chance for stupid errors.
typedef std::bitset<sizeof(int)> IntBits;
bool is_set = IntBits(value).test(position);
or how about this silliness
template<unsigned int Exp>
struct pow_2 {
static const unsigned int value = 2 * po...
How do I search for an object by its ObjectId in the mongo console?
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This gives me an error: TypeError: filter must be an instance of dict, bson.son.SON, or other type that inherits from collections.Mapping
– David Okwii
May 10 '16 at 12:47
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Fastest way to flatten / un-flatten nested JSON objects
...is implementation also has a prototype pollution bug, e.g. unflatten({"foo.__proto__.bar": 42})
– Alex Brasetvik
Feb 19 at 14:06
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How do I find where JDK is installed on my windows machine?
...hich java
Should output the exact location.
After that, you can set JAVA_HOME environment variable yourself.
In my computer (Mac OS X - Snow Leopard):
$ which java
/usr/bin/java
$ ls -l /usr/bin/java
lrwxr-xr-x 1 root wheel 74 Nov 7 07:59 /usr/bin/java -> /System/Library/Frameworks/JavaV...
How can I get the count of milliseconds since midnight for the current?
...meMillis();
System.out.println(new Date(timeNow));
Fri Apr 04 14:27:05 PDT 2014
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ModelState.IsValid == false, why?
Where can I find the list of errors of which make the ModelState invalid? I didn't see any errors property on the ModelState object.
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How to change the docker image installation directory?
...mnt"
– mbarthelemy
Jun 23 '14 at 17:05
6
Doesn't work in Fedora. See my answer if your distro is ...