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authorPatrick Spek <p.spek@tyil.nl>2022-01-18 14:47:47 +0100
committerPatrick Spek <p.spek@tyil.nl>2022-01-18 14:47:47 +0100
commit0101469af3e1bfef9d5583fa9b0746435f21903b (patch)
tree9151590f9c678699ea453db84099db260e2ee12a /content/posts
parent03fd81e0eb75eada5028a2031f6dbc6dd91bcf4b (diff)
downloadblog-0101469af3e1bfef9d5583fa9b0746435f21903b.tar.gz
blog-0101469af3e1bfef9d5583fa9b0746435f21903b.tar.bz2
Remove part 2 of hackerrank solutions for now
I hope to find the will to fix this for Hugo.
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----
-layout: language-war
-date: 2018-10-11
-title: "Hackerrank solutions: Python 3 and Perl 6 (part 2)"
-tags:
-- Hackerrank
-- Perl6
-- Python
-- Python3
-- Programming
-- Raku
----
-
-{% markdown %}
-# Hackerrank solutions: Python 3 and Perl 6 (part 2)
-{% endmarkdown %}
-
-{% markdown %}
-As a continuation of the [previous
-part](/post/2018/09/13/hackerrank-solutions-python3-and-perl6-part-1/) of this
-series, I will be continuing to work through some Hackerrank challenges for
-Python 3, and compare the solutions to how I would solve them in a language I'm
-more proficient in, Perl 6. In this post, I will work through some of the
-Python 3 string challenges from Hackerrank.
-
-Raiph [posted a comment on
-Reddit](https://www.reddit.com/r/perl6/comments/9ffc2p/hackerrank_solutions_python_3_and_perl_6_part_1/e5xml3m)
-suggesting a slightly different layout, which I will be using for this post.
-Additional comments are always welcome as I try to improve the format.
-{% endmarkdown %}
-
-{% admonition_md Disclaimer %}
-Once again I'd like to make clear I'm trying to stick to the original
-Hackerrank challenges by not using any imports not specifically used in the
-original challenge. If you have suggestions for Python 3 or Perl 6 modules to
-make a given task easier, I still appreciate them, but I won't update my
-solutions to use a module.
-{% endadmonition_md %}
-
-{% markdown %}
-## Challenges
-{% endmarkdown %}
-
-<div class="language-war">
- <div class="language-announcer">
-
-{% markdown %}
-### String Split and Join
-
-This challenge involves a string containing spaces, where the spaces are to be
-replaced with dashes (`-`) instead.
-{% endmarkdown %}
-
- </div>
- <div class="language-arena">
- <div class="language-challenger">
- <div class="language-code">
-
-{% highlight python3 tio=https://tio.run/##K6gsycjPM/7/PyU1TaG4ICezJD4xLyU@Kz8zTyMnMy9V04pLAQiKUktKi/IUlHSV9OBSemDlGkoKSpqa/wuKMvNKNNAMyMwrKC3R0ARKp@XnKyQlFgFxFQA %}
-def split_and_join(line):
- return "-".join(line.split(" "))
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-I personally am not too fond that `join` takes a list of words to join
-together, whereas `split` takes a word to split with. It feels a little
-inconsistent. It also doesn't allow me to read the code logically from left to
-right.
-{% endmarkdown %}
-
- </div>
- </div>
- <div class="language-defender">
- <div class="language-code">
-
-{% highlight perl6 tio=https://tio.run/##K0gtyjH7/7@4NEmhuCAns0Q3MS9FNys/M09BQyUnMy9VU6GaSwEIwBw9sBINJQUlTT2QGg0lXSVNrtr/KlqefnrFOaVFBXpqqKboFSdW/k/Lz1dISiwC4ioA %}
-sub split-and-join ($line) {
- $line.split(" ").join("-")
-}
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-The Perl 6 solution to the challenge does the same as the Python variant. Even
-the function names are the same! The biggest difference is that I can chain the
-functions from left to right, leading to clearer code.
-{% endmarkdown %}
-
- </div>
- </div>
- </div>
- <div class="language-announcer">
-
-{% markdown %}
-### What's Your Name?
-
-The next challenge is a simply string formatting task. You get two inputs, a
-first name and a last name, and have to put it in a string which will be
-printed to `STDOUT`.
-{% endmarkdown %}
-
- </div>
- <div class="language-arena">
- <div class="language-challenger">
- <div class="language-code">
-
-{% highlight python3 tio=https://tio.run/##XYzBCsIwEETv/YqxUEigePHmD@jZm6cSyRYj22ww2UK/PobqyWEOAzPz0laeEk@1epqR3iGWaVbmKbqFjBvxsOcOTXtl@isxC4bcfMBdFC/NBZ54JY@2EKQdeOwx4Pu39R8bYtJi7IhfsPWiwUu3uoib5KzLBw %}
-def print_full_name(a, b):
- print("Hello %s %s! You just delved into python." % (a, b))
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-Before you begin, I know this can be done using `f""` strings, and that was my
-first attempt to use as well. However, Hackerrank did not accept this,
-complaining about invalid syntax, so I assume they're running an older Python 3
-than I do.
-
-That said, this is a simple `printf` formatted string, which then accepts a
-tuple of arguments to put into the string. `printf` formatted string are very
-powerful in their possibilities, and it's clear to read.
-{% endmarkdown %}
-
- </div>
- </div>
- <div class="language-defender">
- <div class="language-code">
-
-{% highlight perl6 tio=https://tio.run/##K0gtyjH7/7@4NEmhoCgzr0Q3rTQnRzcvMTdVQyVRR0ElSVOhmksBCIoTKxWUPFJzcvIVVBKB4ooKkfmlClmlxSUKKak5ZakpCkDd@QoBQPMUzPSUuGr/Y5in5emnl55aAjQVytL875NYVFTJFZ6YkwMA %}
-sub print-full-name($a, $b) {
- say "Hello $a $b! You just delved into Perl 6."
-}
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-Perl 6 has double-quote semantics that many people may be familiar with from
-other languages. When you insert a variable in a double-quoted string, it's
-`.Str` value will be used. That is to say, the value will be converted to a
-`Str` if required, and then put into the string.
-
-If you need it or want it for clarity, you can also use `"Hello {$a}"` in Perl
-6, allowing you to use it similarly to Python 3's `f""` strings.
-{% endmarkdown %}
-
- </div>
- </div>
- </div>
- <div class="language-announcer">
-
-{% markdown %}
-### Mutations
-
-You are given a string _string_, an integer _position_ and a character
-_character_. In _string_, replace the character at _position_ to the given
-_character_. The position is counted from starting point 0, so I don't have to
-think about differences between what a human or computer considers to be
-position 1 in a string.
-{% endmarkdown %}
-
- </div>
- <div class="language-arena">
- <div class="language-challenger">
- <div class="language-code">
-
-{% highlight python3 tio=https://tio.run/##VY5BC8IwDIXv/RVhpxaKIN4Ef4mIjNm5iCYlTQ/79bXrpmIuyeN975E468R0KOUWRnhl7TVckwrS3a7LQ@SEikwehqmXftAg7migzqITnOCJSTfc/YzzJ3ipyDdqGiBBsxB03e7BSLbxrsTaoPb/C6SY1ToPi7WJptbLlZHZ7I28AQ %}
-def mutate_string(string, position, character):
- chars = list(string)
- chars[position] = character
-
- return "".join(chars)
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-This is basically what the example showed as well that came with the challenge,
-so wasn't too hard to solve. My only complaint was that I couldn't call my list
-"list", because that's a reserved keyword.
-{% endmarkdown %}
-
- </div>
- </div>
- <div class="language-defender">
- <div class="language-code">
-
-{% highlight perl6 tio=https://tio.run/##K0gtyjH7/7@4NEkht7QksSRVt7ikKDMvXUFDBcLQUVApyC/OLMnMzwMykzMSixKTS1KLNBWquRSAILdSwSEns7hEwVYBqkEvOT83yRosCZaJhuuPBSmCm2DNhVCjl5WfmWfNVfsfxQ0aKlqefnrpqSVAizFYmnrFiZX/0/LzuQy5igA %}
-sub mutate-string ($string, $position, $character) {
- my @list = $string.comb;
- @list[$position] = $character;
-
- @list.join;
-}
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-The Perl 6 variant does the same things as the Python variant. `comb` without
-arguments converts a string to a list of characters, and `join` without
-arguments joins a list together to a string.
-{% endmarkdown %}
-
- </div>
- </div>
- </div>
- <div class="language-announcer">
-
-{% markdown %}
-### Find a String
-
-In the following challenge you are given a string _string_, and a substring
-_sub\_string_. The challenge is to find how often a substring occurs in the
-_string_. The substrings may overlap one another, so the string `"ABCDCDC"`
-contains the substring `"CDC"` twice.
-{% endmarkdown %}
-
- </div>
- <div class="language-arena">
- <div class="language-challenger">
- <div class="language-code">
-
-{% highlight python3 tio=https://tio.run/##XU67CsMwDNz9FTfaxENKt4CHPv4ilNCHkwqKbBx76Ne7bhxIqYSQdNzp5N/x6Xif88OOuLvEcZjTbY6BeJK1aRRkqLPqBEosRBi0YllHF0AgRrjyZGWr8bK8qtUq@QaNqGBPHaGprO32Bcb8eG26zbIx2FXPYGMKXOHsCz/K//eJfYpSaayDUvlwPJ1LilIf %}
-def count_substring(string, sub_string):
- count = 0
-
- for i in range(0, len(string)):
- if string[i:i + len(sub_string)] == sub_string:
- count += 1
-
- return count
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-As solution to this challenge I loop through the entire _string_, and check
-whether it contains the _sub\_string_ at that point. If it does, I increment
-_count_ by 1. Now, I learned that Python also has the inline `if`, just like
-Perl 6 does, however, it also *needs* an `else` block. That put me off from
-using it in this situation. I think it puts me off from using it in most
-situations, actually. With an `else` coming after it, it just becomes messy to
-read, in my opinion.
-{% endmarkdown %}
-
- </div>
- </div>
- <div class="language-defender">
- <div class="language-code">
-
-{% highlight perl6
-tio=https://tio.run/##K0gtyjH7/7@4NEkhOb80r0QXyCouKcrMS1fQUIEwdBRUgIK6EI6mQjUXZ2pOam6xAlRaoa5OIdcqvwxoUGKBPpJSfa7a/2hmaqhoefrppaeWAM2EsjT1ihMr/zs6ObsAIRcQAwA %}
-sub count-substring ($string, $sub-string) {
- elems $string ~~ m:overlap/$sub-string/
-}
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-The Perl 6 version makes use of some regex magic, and the `elems` subroutine.
-`elems` returns the number of elements in a list, which in this case would be
-the number of matches found by the regex. The `m:overlap//` makes a regex to
-*m*atch, with *overlap*ping strings.
-{% endmarkdown %}
-
- </div>
- </div>
- </div>
- <div class="language-announcer">
-
-{% markdown %}
-### String Validators
-
-In the following challenge, the program is given a string _s_, and have to
-validate a number of properties on this string. These are, in order, whether
-they contain
-
-- alphanumeric characters (a-z, A-Z or 0-9),
-- alphabetic characters (a-z or A-Z),
-- digits (0-9),
-- lowercase characters (a-z),
-- uppercase characters (A-Z).
-
-If any character in the given string passes a validation, it must print
-`"True"`, otherwise it must print `"False"`.
-
-{% endmarkdown %}
-
- </div>
- <div class="language-arena">
- <div class="language-challenger">
- <div class="language-code">
-
-{% highlight python3 tio=https://tio.run/##hZLNioMwEIDvPsXQPdTAIrS9CR72sk@wt1JCVtMaqklIIqWUPrubn6p1MZib38x8zmQi76YW/ND37AwYc9JSjKEoYItxSxjHeJsnYI@GAhiXnUlR4kFZ0/Lq6MN/urMhDe/aTQ7fpNH0853Lmizwil2YWeCNuFG1wDspJ@7xMzRzFso2RJRtERqmTapRPpbZybgwr4aPryZPQHjlazKmPUrfSqYBp/wCflRHk7jWzfhPa1FcG/JXtOGKZlqPYtohf0Ubbnim9SimHfJXtGFBM61HMe2QH7QQvFd6d@/K7zEkZg6lCI3hTAs1vkS3fAvd7l1s@pNUjA@Kow2dUN9//ZbVbn/4@AM %}
-if __name__ == '__main__':
- s = input()
-
- checks = {
- "alnum": False,
- "alpha": False,
- "digit": False,
- "lower": False,
- "upper": False
- }
-
- for char in list(s):
- if not checks["alnum"] and char.isalnum():
- checks["alnum"] = True
-
- if not checks["alpha"] and char.isalpha():
- checks["alpha"] = True
-
- if not checks["digit"] and char.isdigit():
- checks["digit"] = True
-
- if not checks["lower"] and char.islower():
- checks["lower"] = True
-
- if not checks["upper"] and char.isupper():
- checks["upper"] = True
-
- keys = list(checks.keys())
- keys.sort()
-
- for key in keys:
- print(checks[key])
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-As stated in the disclaimer, I don't want to make use of any `import`
-statements unless these are explicitly given in the original challenges. This
-means I can't use regexes, as these are stuffed away in the `re` packages in
-Python. Luckily, Python has the correct check available as a method on the
-string object, so I can still check them in a single line.
-
-I first tried to call the methods on _s_ directly, but this seemed to require
-the entire string to match the check, instead of just any character in the
-string. So I had to loop through the string by character, which I did. If any
-character is found to validate, the appropriate key in the _checks_ dict will
-be set to `True`. Once I've walked through the entire string, I sort the _keys_
-from _checks_ so I can be sure they're printed in the right order.
-{% endmarkdown %}
-
- </div>
- </div>
- <div class="language-defender">
- <div class="language-code">
-
-{% highlight perl6
-tio=https://tio.run/##K0gtyjH7/7@4NEnB19HTT6GaSwEIcisVVIoVbBVUtDz99NJTS6y5wMLFiZUKxfkgqbo6BX2bxJy80lw7fWvscgUZiTjkUjLTM0twyOXkl6cW4ZArLSiAyNX@/@@YlJxiaGSsDAA %}
-sub MAIN {
- my $s = $*IN.get;
-
- say so $s ~~ /<alnum>/;
- say so $s ~~ /<alpha>/;
- say so $s ~~ /<digit>/;
- say so $s ~~ /<lower>/;
- say so $s ~~ /<upper>/;
-}
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-Perl 6 does have regexes available in the main namespace by default, so that
-made this challenge a lot easier to work with. `$*IN` in a special variable
-that refers to `STDIN`, and the `.slurp` method reads all remaining data from
-the buffer.
-
-The next 5 lines all do a `say`, which acts like `print` in Python 3. The `so`
-function coerces a value to become a `Bool`. When a `Bool` is given to `say`,
-it will be coerced to a string representation again, and become either `"True"`
-or `"False"`. The smartmatch operator `~~` has already been covered in the
-previous post, so I recommend you read that as well if you haven't yet.
-
-In Perl 6, regexes are (usually) delimited by the `/` character. The `<alnum>`,
-`<alpha>` etcetera parts are [predefined character classes][classes] in Perl 6
-regexes. These check for exactly what we need in the challenges, so were a good
-pick to solve them.
-
-[classes]: https://docs.perl6.org/language/regexes.html#Predefined_character_classes
-{% endmarkdown %}
-
- </div>
- </div>
- </div>
- <div class="language-announcer">
-
-{% markdown %}
-### Text Wrap
-
-You are given a string _s_ and a width _w_. The string should be split over
-multiple lines so it is never more wide than _w_.
-{% endmarkdown %}
-
- </div>
- <div class="language-arena">
- <div class="language-challenger">
- <div class="language-code">
-
-{% highlight python3 tio=https://tio.run/##K6gsycjPM/7/PzO3IL@oRKEktaKkvCixgIsrJTVNAcTSKC4pysxL11HITayIL89MKcnQtOJSAIKi1JLSojwFpZg8Jb2s/Mw8DZhePRzaNP8XAIVKNMDSmXkFpSUamjoKIBEoBwj@Ozo5u7i6uXt4enn7@Pr5BwQGBYeEhoVHREZxmQIA %}
-import textwrap
-
-def wrap(string, max_width):
- return "\n".join(textwrap.wrap(string, max_width))
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-This challenge introduces the first Python module: `textwrap`. This makes the
-challenge very easy to solve as well, using the `wrap` function exposed by the
-module. This function makes a list of strings, each no longer than the given
-width. I then join these together with newlines to get the desired output.
-{% endmarkdown %}
-
- </div>
- </div>
- <div class="language-defender">
- <div class="language-code">
-
-{% highlight perl6 tio=https://tio.run/##K0gtyjH7/7@4NEmhvCixQEFDpbikKDMvXUdBpTwzpSRDU6GaSwEIoMJ6yfm5SRpQKb2s/Mw8DaWYPCVNrtr/IO0aKlqefnrpqSVA7VCWnmdeiaZecWLlf0cnZxdXN3cPTy9vH18//4DAoOCQ0LDwiMgoLlMA %}
-sub wrap ($string, $width) {
- $string.comb($width).join("\n")
-}
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-For the Perl 6 solution, I have not used an additional module, as all the
-functionality are in the core namespace. I actually made a module in Perl 6 for
-a less primitive wrapping functionality, called [`String::Fold`][string::fold].
-
-In this solution, I use `comb` with the `$width` argument. This returns a list
-of strings, each no longer than the given width, just like Python's
-`textwrap.wrap`. I can then join these together with newlines as well to get
-the same result.
-
-[string::fold]: https://modules.perl6.org/dist/String::Fold:cpan:TYIL
-{% endmarkdown %}
-
- </div>
- </div>
- </div>
- <div class="language-announcer">
-
-{% markdown %}
-### Designer Door Mat
-
-This challenge is more complex than previous challenges. The task at hand is to
-"draw" a certain "design" as the output. For the input, you are given both a
-height _y_ and a width _x_, however _x_ must always be _y_ × 3, so you can
-ignore the second argument.
-
-This one is much simpler to explain using two examples. The first example is
-the output if the input were `7 21`.
-{% endmarkdown %}
-
-{% highlight text %}
----------.|.---------
-------.|..|..|.------
----.|..|..|..|..|.---
--------WELCOME-------
----.|..|..|..|..|.---
-------.|..|..|.------
----------.|.---------
-{% endhighlight %}
-
-{% markdown %}
-In the second example, the input is `11 33`.
-{% endmarkdown %}
-
-{% highlight text %}
----------------.|.---------------
-------------.|..|..|.------------
----------.|..|..|..|..|.---------
-------.|..|..|..|..|..|..|.------
----.|..|..|..|..|..|..|..|..|.---
--------------WELCOME-------------
----.|..|..|..|..|..|..|..|..|.---
-------.|..|..|..|..|..|..|.------
----------.|..|..|..|..|.---------
-------------.|..|..|.------------
----------------.|.---------------
-{% endhighlight %}
-
- </div>
- <div class="language-arena">
- <div class="language-challenger">
- <div class="language-code">
-
-{% highlight python3 tio=https://tio.run/##zZDNS8MwGMbv@SseMwbJlrbrehCEnWS3DS@CBxGpNFsCJQ1p5xD832s@Nh2I7GpyCHmf3/u8H/ZjUJ2pxnFyg@LQu@JNm0Kad9gkEKKk3qsBK2gzMKaNPQyM571ttX/58@KFk6NuBuWJEzpDRVTd7s45p3CGkqPAkhMywWNnERiy6xxabaRH4Wqzl6wUUcHc83cE/pjOvDZ1r2TvLRmL@MwbRctIfKuxYOonA7tI9E3xc/mQYV1A6bQPl2IKRjPqqYQL0PwzD/8fCx@7IHgcY6ubppVxAPLbMRZKSSxoqa8idV5xkfSn9eb@Ybum4gpOUslNd5Tur92FsMBCIPvfuxvHWyzLLw %}
-#! /usr/bin/env python3
-
-height = int((input().split())[0])
-width = height * 3
-half = int((height - 1) / 2)
-
-# Top half
-for line in range(1, half + 1):
- non_dashes = ((line * 2) - 1)
- dashes = int((width - (non_dashes * 3)) / 2)
-
- print("%s%s%s" % ("-" * dashes, ".|." * non_dashes, "-" * dashes))
-
-# Middle line
-print("%s%s%s" % (
- "-" * (int(width / 2) - 3),
- "WELCOME",
- "-" * (int(width / 2) - 3)
-))
-
-# Lower half
-for line in range(half, 0, -1):
- non_dashes = ((line * 2) - 1)
- dashes = int((width - (non_dashes * 3)) / 2)
-
- print("%s%s%s" % ("-" * dashes, ".|." * non_dashes, "-" * dashes))
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-I split the code up in a top half, middle line and lower half, to make it
-easier to reason about. The `for` loops contain some logic to get the right
-output on every line. I found out that `range` supports a third argument,
-allowing me to count down with it as well, which was perfect for this
-situation.
-{% endmarkdown %}
-
- </div>
- </div>
- <div class="language-defender">
- <div class="language-code">
-
-{% highlight perl6 tio=https://tio.run/##zZBBTsMwEEX3PsXgdpEgxVFSqSwiVqiLSi1skFiiIE@xpeBEdtpQhZyDo3CAHix0UpKGSuzxypp5/8/XL9Bm87adXEG4dTZ80SZEs4OCxoy97WGqUL@qEm5her28Fy7b2kJUuZVOKEylWJoy6bhKy1IR9iM4fMLstFFptgkGG68HAoh8OHxBnDA2gce8AALZJrcQCfFLVTM4PvIyuQlk6hS6zuqZzsQ@eSUDM9qfQgXH30hIyfzhNKlcugde84DDey9vai4@RDc4S5sLhiesofBrLWWGkGmDbOzl9QnoFqWc@c3TYnX3sF7U8DfCu0ZWeYX23Il3UYovLO7QOvzX7bTtDcTRNw %}
-#! /usr/bin/env perl6
-
-my $height = $*IN.slurp.words.head.Int;
-my $width = $height × 3;
-my $half-height = ($height - 1) ÷ 2;
-
-# Top half
-for 1..$half-height {
- my $non-dashes = ($_ × 2) - 1;
- my $dashes = ($width - ($non-dashes × 3)) ÷ 2;
-
- say "{"-" x $dashes}{".|." x $non-dashes}{"-" x $dashes}";
-}
-
-# Middle line
-say "{"-" x (($width ÷ 2) - 3)}WELCOME{ "-" x (($width ÷ 2) - 3)}";
-
-# Lower half
-for (1..$half-height).reverse {
- my $non-dashes = ($_ × 2) - 1;
- my $dashes = ($width - ($non-dashes × 3)) ÷ 2;
-
- say "{"-" x $dashes}{".|." x $non-dashes}{"-" x $dashes}";
-}
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-As usual, the code is functionally the same. I must admit I like the functional
-style to get an `Int` from the first argument much more than the way I do it in
-Python, though.
-
-A thing I learned is that the `..` operator that generates a sequence does not
-have a way to make a sequence that counts down, so I had to use `.reverse` on a
-sequence that counts up. I had expected this to Just Work as I expected and
-count down if the left hand side would be larger than the right hand side.
-
-You may notice some fancy Unicode characters in the source, namely `×` for
-multiplication, and ÷ for division. Perl 6 allows Unicode characters in the
-source files, which can oftentimes lead to prettier code. In this particular
-instance, there's no big difference in code readability, though. And for those
-who don't yet have a modern editor that can make Unicode characters, do not
-worry, as the ASCII equivalents (`*` and `/` respectively) still work as well.
-{% endmarkdown %}
-
- </div>
- </div>
- </div>
- <div class="language-announcer">
-
-{% markdown %}
-### String Formatting
-
-In this challenge, you are to produce a table with four columns. The columns
-should contain the decimal, octal, hexadecimal and binary values of the row
-numbers. The function receives an int _number_. The table should contain that
-many rows, starting with row number 1.
-{% endmarkdown %}
-
- </div>
- <div class="language-arena">
- <div class="language-challenger">
- <div class="language-code">
-
-{% highlight python3 tio=https://tio.run/##jZFNCoMwEIX3nmIQhIQG0XYn9CwSTawpJoYYqVJ6dht/W7uQDlll3vveTKJ7W9bqMgyMF6CNUDYtaiOptZwh1cqMG5x44ErSLn0IZku4QsUV8p9Rkr38cJavWuxNYncJAoQCQ9WNo5jA3IcTxAtvLMZzIWnliI72YQkcmnvbWLRl4s1S53Y1JPV/lpJ3dJeUdDtjqzU36ACQCUVNv3iz49DNND0m8oMG1uNDAGgZhMyLkO/hyBKE8fD7EyNKKN1ahF33HL0B %}
-def print_formatted(number):
- max_width = len("{0:b}".format(number))
-
- for i in range(1, number + 1):
- decimal = "{0}".format(i).rjust(max_width)
- octal = "{0:o}".format(i).rjust(max_width)
- hexadecimal = "{0:x}".format(i).upper().rjust(max_width)
- binary = "{0:b}".format(i).rjust(max_width)
-
- print("%s %s %s %s" % (decimal, octal, hexadecimal, binary))
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-In the Python 3 solution I first calculate the max width I need to take into
-account. Then I loop from 1 until _number_ to get the right amount of rows.
-Each iteration, I format the number correctly, and then print it out using a
-printf format string.
-
-The hardest part of this challenge was to get formatting right the way
-Hackerrank wanted it. But I guess that was the entire point of the challenge.
-{% endmarkdown %}
-
- </div>
- </div>
- <div class="language-defender">
- <div class="language-code">
-
-{% highlight perl6 tio=https://tio.run/##XY9NCsIwEIX3PcUQIiRiB1tEBPEA3bhxK0iq0VZMWpIUK1KvXmNb/HurGWbeN29KaS7ztrVVCqXJtQuPhVHCOXkARnWlUmk43APwUjegStThNT@4DFYwjDEVVrKY48YZ3GfC2OV7vYeF1nn0yVsYGd0/jMYSqGuYcTwXuWYECIcHkK0my6BDeDtEiMOhIcZLv2Dskh8Z3U2A7vo8C/6po/lXE3Pe52uCpv17mdFxssaTdJhox9t4@gQ %}
-sub print-formatted ($number) {
- my $max-width = $number.base(2).Str.chars;
- my $format-string = ("%{$max-width}s" xx 4).join(" ") ~ "\n";
-
- for 1..$number {
- $format-string.printf($_, $_.base(8), $_.base(16), $_.base(2));
- }
-}
-{% endhighlight %}
-
- </div>
- <div class="language-commentary">
-
-{% markdown %}
-The Perl 6 solution starts of the same, in that it first calculates the max
-width I need to take into account. Next, however, I generate the format string
-using the `$max-width` to make the `printf` subroutine pad it for me. The `xx`
-operator makes a total of 4 such strings, and puts them into a list, which I
-can then `join` together with a space character, and add a `\n` at the end of
-it (the `~` operator is for string concatenation).
-
-I'm assuming something similar is possible in Python 3 as well, and I would
-like to have an example so I can compare it more fairly.
-
-In the Perl 6 solution I am also able to make use of the `base` method to
-convert the numbers into the right base, something I could not find for Python
-3.
-{% endmarkdown %}
-
- </div>
- </div>
- </div>
-</div>
-
-{% markdown %}
-## Wrap-up
-
-This time I did not do all of the challenges, as the post would probably get
-too long. I still did 8 of them, and might do the rest of the string challenges
-in a later part anyway.
-
-I still find Perl 6 to produce much cleaner code, which is shown best with the
-first challenge. In Perl 6 (`$line.split(" ").join("-")`), I can read from left
-to right to see what I'm doing: I have a `$line`, which I split, and then join.
-In the Python variant (`"-".join(line.split(" "))`), it is much less clear what
-the actual item I'm working on is, as it's hidden inbetween the `join` and
-`split` calls.
-
-Of course, I'm still not an expert on Python 3 code, so I'm sure that there are
-many parts that could be written in a cleaner fashion. I'm still open for
-feedback to improve my Python 3 skills (hence I'm publishing these posts), so
-please let me know if you know better ways to solve some challenges.
-{% endmarkdown %}