Tiny java code...

27 Mar 2015

This one was super easy so I did a quick comparison of a couple of ways you can do it; the goal is to count all the alphanumeric (a-zA-Z0-9) characters in the text of a Sherlock Holmes book. There’s probably other ways do do it because there’s lots of ways to do literally anything, but the fastest one here is stripping out all non-alphanumeric characters (\W).

//*********************************************//
//                                             //
//        EASY DAILY PROGRAMMING TASK #19      //
//        ALPHANUMERIC CHARACTER COUNTING      //
//                                             //
//*********************************************//

public void count1(String text) {
    long start = System.currentTimeMillis();
    int count = 0;

    for (char c : text.toCharArray()) {
        if ((c + "").matches("[a-zA-Z0-9]")) {
            count++;
        }
    }

    long end = System.currentTimeMillis();
    System.out.println("Count 1: " + count + " Time taken: " + (end - start));
}

public void count2(String text) {
    long start = System.currentTimeMillis();
    int count1 = text.length();
    text = text.replaceAll("\\w", "");
    long end = System.currentTimeMillis();
    System.out.println("Count 2: " + (count1 - text.length()) + " Time taken: " + (end - start));
}

public void count3(String text) {
    long start = System.currentTimeMillis();
    text = text.replaceAll("\\W", "");
    long end = System.currentTimeMillis();
    System.out.println("Count 3: " + text.length() + " Time taken: " + (end - start));
}

Countiung all alphanumeric characters in Sherlock.txt:
Count 1: 432188 Time taken: 269
Count 2: 432188 Time taken: 53
Count 3: 432188 Time taken: 22

tinyjavacode:

The new hardcore

25 Mar 2015

Trying some new hardcore - Assembly in Emacs 😁

How to adjust widget’ size in Qt

24 Mar 2015

Have you ever thought on how this:

could be turned to this:

without manually setting per-pixel sizes?

It’s simple as 1-2! Just take a look at the top of the UI editor and you’ll find a set of buttons, dedicated to do this adjustment for you:

Yet, there is just one small tip: first you should select a containing widget, whose children will be rearranged.

Like this:

Note the selected parent widget for vertical_layout.

Decorator pattern in Python

24 Mar 2015

Just found some interesting way of implementing Decorator design pattern in Python.

As Jason Smith said in his book (Elemental Design Patterns), “design patterns may be implemened in different ways in different programming languages”.

That’s said, design patterns are not some set of classes which will be implemented in a very similar way in different languages - they are just a way of doing something.

Thus, Decorator pattern is a way of wrapping some method’s or class’ behaviour. In Python it may be done with Context Managers:

from contextlib import contextmanager

@contextmanager
def tag(name):
    print "<%s>" % name,
    yield
    print "</%s>" % name,

with tag("h1"):
    print "moo",

print

with tag("div"):
    print "foo",

This code will end up wrapping print "foo" and print "moo" methods with printing some HTML tags around ‘em:

<h1>moo</h1>
<div>foo</div>

That is interesting as it implements Decorator design pattern in a bit hard-coded way, but using language features, not OOP ones.

Compare it to the “standard” OOP implementation in Python:

# -*-coding:utf-8 -*-
class SimpleText(object):
    def __init__(self, text):
        self.text = text

    def content(self):
        return self.text

    def __str__(self):
        return self.content()

class TagDecorator(SimpleText):
    def __init__(self, text, tag):
        super(TagDecorator, self).__init__(text)
        self.tag = tag

    def content(self):
        return '<{0}>{1}</{0}>'.format(self.tag, super(TagDecorator, self).content())

a = SimpleText('moo')
print('SimpleText: %s' % a)

b = TagDecorator('moo', 'h1')
print('TagDecorator (h1): %s' % b)