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Regular expression for floating point numbers
.... and [0-9] instead of \d to avoid escaping issues in some languages (like Java).
Thanks to the nameless one for originally recognizing this.
One relatively simple pattern for matching a floating point number is
[+-]?([0-9]*[.])?[0-9]+
This will match:
123
123.456
.456
See a working exampl...
HashMap and int as key
...lt;Integer, MyObject> myMap = new HashMap<Integer, MyObject>();
Java will automatically autobox your int primitive values to Integer objects.
Read more about autoboxing from Oracle Java documentations.
share
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Simplest way to serve static data from outside the application server in a Java web application
I have a Java web application running on Tomcat. I want to load static images that will be shown both on the Web UI and in PDF files generated by the application. Also new images will be added and saved by uploading via the Web UI.
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How can I count occurrences with groupBy?
...h each group... and then Collectors.counting() to do the counting:
import java.util.*;
import java.util.stream.*;
class Test {
public static void main(String[] args) {
List<String> list = new ArrayList<>();
list.add("Hello");
list.add("Hello");
list...
What does “var FOO = FOO || {}” (assign a variable or an empty object to that variable) mean in Java
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i like to say it's the #ifndef/#define for javascript :)
– Darren Kopp
Jun 22 '11 at 17:15
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R: += (plus equals) and ++ (plus plus) equivalent from c++/c#/java, etc.?
Does R have a concept of += (plus equals) or ++ (plus plus) as c++/c#/others do?
8 Answers
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Properly removing an Integer from a List
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Java always calls the method that best suits your argument. Auto boxing and implicit upcasting is only performed if there's no method which can be called without casting / auto boxing.
The List interface specifies two remove...
Missing return statement in a non-void method compiles
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The Java compiler is smart enough to find the unreachable code ( the code after while loop)
and since its unreachable, there is no point in adding a return statement there (after while ends)
same goes with conditional if
publi...
Difference between matches() and find() in Java Regex
... {
Pattern p = Pattern.compile("\\d");
String candidate = "Java123";
Matcher m = p.matcher(candidate);
if (m != null){
System.out.println(m.find());//true
System.out.println(m.matches());//false
}
}
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What is the difference between compare() and compareTo()?
What is the difference between Java's compare() and compareTo() methods? Do those methods give same answer?
16 Answers
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