This is a huge topic, with answers from 3 lines of code to entire research magazines. I will outline the most common such techniques and their results. Comparing histograms One of the simplest & fastest methods. Proposed decades ago as a means to find picture simmilarities. The idea is that a forest will have a … Read more
There’s a striking difference here. valueOf is returning an Integer object, which may have its values cached between -128 and 127. This is why the first value returns true – it’s cached – and the second value returns false – 128 isn’t a cached value, so you’re getting two separate Integer instances. It is important … Read more
You can simply use Apache Commons Lang: result = ObjectUtils.compare(firstComparable, secondComparable)
When you compile a number literal in Java and assign it to a Integer (capital I) the compiler emits: Integer b2 =Integer.valueOf(127) This line of code is also generated when you use autoboxing. valueOf is implemented such that certain numbers are “pooled”, and it returns the same instance for values smaller than 128. From the … Read more
Another solution for this old post (for those that it might help) : public class Version implements Comparable<Version> { private String version; public final String get() { return this.version; } public Version(String version) { if(version == null) throw new IllegalArgumentException(“Version can not be null”); if(!version.matches(“[0-9]+(\\.[0-9]+)*”)) throw new IllegalArgumentException(“Invalid version format”); this.version = version; } @Override … Read more
O(n): The Counter() method is best (if your objects are hashable): def compare(s, t): return Counter(s) == Counter(t) O(n log n): The sorted() method is next best (if your objects are orderable): def compare(s, t): return sorted(s) == sorted(t) O(n * n): If the objects are neither hashable, nor orderable, you can use equality: def … Read more
LIKE and the equality operator have different purposes, they don’t do the same thing: = is much faster, whereas LIKE can interpret wildcards. Use = wherever you can and LIKE wherever you must. SELECT * FROM user WHERE login LIKE ‘Test%’; Sample matches: TestUser1 TestUser2 TestU Test
Sounds like a job for XMLUnit http://www.xmlunit.org/ https://github.com/xmlunit Example: public class SomeTest extends XMLTestCase { @Test public void test() { String xml1 = … String xml2 = … XMLUnit.setIgnoreWhitespace(true); // ignore whitespace differences // can also compare xml Documents, InputSources, Readers, Diffs assertXMLEqual(xml1, xml2); // assertXMLEquals comes from XMLTestCase } }
More conveniently This can be done more conveniently using Bash’s numeric context: if (( $(echo “$num1 > $num2” |bc -l) )); then … fi Explanation Piping through the basic calculator command bc returns either 1 or 0. The option -l is equivalent to –mathlib; it loads the standard math library. Enclosing the whole expression between … Read more
Tuples are compared position by position: the first item of the first tuple is compared to the first item of the second tuple; if they are not equal (i.e. the first is greater or smaller than the second) then that’s the result of the comparison, else the second item is considered, then the third and … Read more