Parse the comments out of my esoteric code

Question 1

Earlier this week, we learned about how to format esoteric languages for commenting. Today, we're going to do the inverse of that. I need you to write a program or function that parses some well-commented esoteric code and parses the comments out, returning just the code. Using some examples from the previous challenge, here is what well-commented code looks like:

a #Explanation of what 'a' does
 bc #Bc
 d #d
 e #Explanation of e
 fgh #foobar
 ij #hello world
 k #etc.
 l #so on
 mn #and
 op #so forth

Here is what you need to do to extract the code out. First, remove the comment character (#), the space before it, and everything after the comment character.

a 
 bc 
 d 
 e 
 fgh 
 ij 
 k 
 l 
 mn 
 op

Then, collapse each line upwards into a single line. For example, since b is in the second column on line two, once we collapse it up, it will be in the second column on line one. Similarly, c will be put in the third column of line one, and d will be put on the fourth. Repeat this for every character, and you get this:

abcdefghijklmnop

Important note: It seems like the trivial solution is to just remove the comments, remove every space, and join every line. This is not a valid approach! Because the original code might have spaces in it, these will get stripped out with this approach. For example, this is a perfectly valid input:

hello #Line one
 #Line two
 world! #Line three

And the corresponding output should be:

hello world!

The Challenge:

Write a program or function that takes commented code as input, and outputs or returns the code with all the comments parsed out of it. You should output the code without any trailing spaces, although one trailing newline is permissible. The comment character will always be #, and there will always be one extra space before the comments start. # will not appear in the comment section of the input. In order to keep the challenge simpler, here are some inputs you do not have to handle:

You can assume that the code will not have two characters in the same column. For example, this is an input that violates this rule:
```
a #A character in column one
bc #Characters in columns one and two
```
You can also assume that all comment characters appear in the same column. For example, this input:
```
short #this is a short line
 long #This is a long line
```
violates this rule. This also means that # will not be in the code section.
And lastly, you do not have to handle code sections with leading or trailing spaces. For example,
```
 Hello, #
 World! #
```

You may also assume that the input only contains printable ASCII characters.

Examples:

Input:
hello #Line one
 #Line two
 world! #Line three
Output:
hello world!
Input:
E #This comment intentionally left blank
 ac #
 h s #
 ecti #
 on is #
 one c #
 haracte #
 r longer #
 than the #
 last! #
Output:
Each section is one character longer than the last!
Input:
4 #This number is 7
 8 #
 15 #That last comment is wrong.
 16 #
 23 #
 42 #
Output:
4815162342
Input:
Hello #Comment 1
 world #Comment 2
 , #Comment 3
 how #Comment 4
 are #Comment 5
 you? #Comment 6
Output:
Hello world, how are you?
Input:
Prepare #
 for... #
 extra spaces! #
Output:
Prepare for... extra spaces!

You may take input in whatever reasonable format you like, for example, a list of strings, a single string with newlines, a 2d list of characters, etc. The shortest answer in bytes wins!

Question 2

Will we need to accept code with characters lower than the next?

Question 3

Could you add the test case with the empty line with just two spaces (like the hello world! you've showed)? Also, you state: "# will not appear in the comment section of the input.", but can it occur in the code-snippet itself?

Question 4

@KevinCruijssen See my edits

Question 5

@wizzwizz4 I'm not sure if I understand your question

Question 6

@DJMcMayhem Example: do {stuff} while (condition); with the explanation in order do while (condition); #Explainything then {stuff} #Explainything.

Question 7

Jelly, (削除) 8 (削除ここまで) 7 bytes

»/ṣ"#ḢṖ

Try it online!

How it works

»/ṣ"#ḢṖ Main link. Argument: A (array of strings)
»/ Reduce the columns of A by maximum.
 Since the space is the lowest printable ASCII characters, this returns the
 non-space character (if any) of each column.
 ṣ"# Split the result at occurrences of '#'.
 Ḣ Head; extract the first chunk, i.e., everything before the (first) '#'.
 Ṗ Pop; remove the trailing space.

Question 8

That is just ...wow.

Question 9

I am so jelly right now.

Question 10

How do you even hack that into your phone?

Question 11

@simbabque Patience and a lot of copy-pasting.

Question 12

I'm always putting using a 9-iron, maybe it's time I learned how to use a putter when on the green...

Question 13

Python 2, (削除) 48 (削除ここまで) 43 bytes

lambda x:`map(max,*x)`[2::5].split(' #')[0]

Thanks to @xnor for golfing off 5 bytes!

Test it on Ideone.

Question 14

I think you can just do map(max,*x) because max takes any number of arguments and None is small.

Question 15

Right, I always forget that map can be used like that... Thanks!

Question 16

How does the `...`[2::5] trick work?

Question 17

@smls `...` is equivalent to repr(...), so for the list of singleton strings ['a', 'b', 'c'], you get the string "['a', 'b', 'c']". Finally, [2::5] chops off the first two characters ("['") and takes every fifth character of the remaining string.

Question 18

JavaScript (ES6), (削除) 97 (削除ここまで) (削除) 75 (削除ここまで) 60 bytes

Thanks to @Neil for helping golf off 22 bytes

a=>a.reduce((p,c)=>p.replace(/ /g,(m,o)=>c[o])).split` #`[0]

Input is an array of lines.

a is array input
p is previous item
c is current item
m is match string
o is offset

Question 19

I count 96 bytes? Also, the m regexp flag is unnecessary (did you have a $ at one point?) as is the space in (p, c). Finally, I think replace will work out shorter than [...p].map().join.

Question 20

97 for me, both from manual length and userscript, maybe you didn't count the newline, but only because I accidentally included the semicolon

Question 21

I see now - I hadn't copied the ; which isn't required (JavaScript has ASI).

Question 22

Yeah, sorry, I had it to make sure Chromium console puts the function call outside the function body (had it once on a badly written lambda)

Question 23

Oh wow, I didn't realise replace would help so much, that's really neat!

Question 24

Perl, (削除) 35 (削除ここまで) (削除) 34 (削除ここまで) 32 bytes

Includes +1 for -p

Give input on STDIN

eso.pl

#!/usr/bin/perl -p
y/ /0円/;/.#/;$\|=$`}{$\=~y;0円;

Notice that there is a space after the final ;. The code works as shown, but replace 0円 by the literal character to get the claimed score.

Question 25

Very nice code. That $a|=... is rather well done, it took me a while to figure out what you were doing! One question though : *_=a seems to be roughly equivalent to $_=$a, why is that?

Question 26

*_=a is a very obscure glob assignment which aliases the _ globals and the a globals. So it's not so much a copy from $a to $_ but from that point on (global) $a and $_ are actually the same variable. All to save 1 byte...

Question 27

Ok, thanks for the explanation! (and nice improvement thanks to `$\`)

Question 28

Python 2, 187 bytes

def f(x,o=""):
 l=[i[:i.index("#")-1]for i in x]
 for n in range(len(l[0])):
 c=[x[n]for x in l]
 if sum([1for x in c if x!=" "])<1:o+=" "
 else:o+=[x for x in c if x!=" "][0]
 print o

I'm gonna golf this more tomorrow I have school ;)

Question 29

1 for can be reduced to 1for. Also, if the sum of the list (at line 5) can't be negative, you can just check for <1 instead of ==0. Happy school day! :D +1.

Question 30

Ruby, 63 bytes

Basically a port of Dennis' Jelly answer. Takes input as an array of strings.

->a{l,=a
l.gsub(/./){a.map{|m|m[$`.size]||$/}.max}[/(.+) #/,1]}

See it on eval.in: https://eval.in/640757

Question 31

CJam, 12 bytes

Thanks to Sp3000 for saving 2 bytes.

{:.e>_'##(<}

An unnamed block that takes a list of strings (one for each line) and replaces it with a single string.

Try it online!

Explanation

:.e> e# Reduce the list of strings by elementwise maximum. This keeps non-spaces in
 e# favour of spaces. It'll also wreak havoc with the comments, but we'll discard
 e# those anyway.
_'## e# Duplicate and find the index of '#'.
(< e# Decrement that index and truncate the string to this length.

Question 32

J, 30 bytes

(#~[:<./\'#'~:])@(>./&.(3&u:))

Takes a list of strings as input. Basically uses the same approach as Dennis in his Jelly answer.

Commented and explained

ord =: 3 & u:
under =: &.
max =: >./
over =: @
maxes =: max under ord
neq =: ~:
arg =: ]
runningMin =: <./\
magic =: #~ [: runningMin ('#' neq arg)
f =: magic over maxes

Intermediate steps:

 p
Hello #Comment 1
 world #Comment 2
 , #Comment 3
 how #Comment 4
 are #Comment 5
 you? #Comment 6
 maxes p
Hello world, how are you? #Comment 6
 magic
#~ ([: runningMin '#' neq arg)
 3 neq 4
1
 '#' neq '~'
1
 '#' neq '#'
0
 '#' neq maxes p
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1
 runningMin 5 4 2 5 9 0 _3 4 _10
5 4 2 2 2 0 _3 _3 _10
 runningMin '#' neq maxes p
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0
 0 1 0 1 1 0 # 'abcdef'
bde
 'abcdef' #~ 0 1 0 1 1 0
bde
 (maxes p) #~ runningMin '#' neq maxes p
Hello world, how are you? 
 (#~ [: runningMin '#' neq arg) maxes p
Hello world, how are you? 
 ((#~ [: runningMin '#' neq arg) over maxes) p
Hello world, how are you? 
 (magic over maxes) p
Hello world, how are you?

Test case

 f =: (#~[:<./\'#'~:])@(>./&.(3&u:))
 a
Hello #Comment 1
 world #Comment 2
 , #Comment 3
 how #Comment 4
 are #Comment 5
 you? #Comment 6
 $a
6 36
 f a
Hello world, how are you?

Question 33

Javascript (ES6), 63 bytes

a=>a.reduce((p,c)=>p+/(.+?)\s+#/.exec(c)[1].slice(p.length),'')

Takes input as an array of strings.

F=a=>a.reduce((p,c)=>p+/(.+?)\s+#/.exec(c)[1].slice(p.length),'')
input.oninput = update;
update();
function update() {
 try {
 output.innerHTML = F(input.value.trim().split`
`);
 } catch(e) {
 output.innerHTML = 'ERROR: INVALID INPUT';
 }
}

textarea {
 width: 100%;
 box-sizing: border-box;
 font-family: monospace;
}

<h2>Input:</h2>
<textarea id="input" rows="8">
a #Explanation of what 'a' does
 bc #Bc
 d #d
 e #Explanation of e
 fgh #foobar
 ij #hello world
 k #etc.
 l #so on
 mn #and
 op #so forth
</textarea>
<hr />
<h2>Output:</h2>
<pre id="output">
</pre>

Question 34

Retina, 32 bytes

Byte count assumes ISO 8859-1 encoding.

Rmr` #.+|(?<=^(?<-1>.)+).+?¶( )+

Try it online!

Question 35

Pyke, (削除) 15 (削除ここまで) 10 bytes

,FSe)s\#ch

Try it here!

Port of the Jelly answer

, - transpose()
 FSe) - map(min, ^)
 s - sum(^)
 \#c - ^.split("#")
 h - ^[0]

Question 36

C# (削除) 157 (削除ここまで) 122 Bytes

Golfed 35 bytes thanks to @milk -- though I swear I tried that earlier.

Takes input as a 2-d array of characters.

string f(char[][]s){int i=0;foreach(var x in s)for(i=0;x[i]!=35;i++)if(x[i]!=32)s[0][i]=x[i];return new string(s[0],0,i);}

157 bytes:

string g(char[][]s){var o=new char[s[0].Length];foreach(var x in s)for(int i=0;x[i]!=35;i++)if(x[i]!=32|o[i]<1)o[i]=x[i];return new string(o).TrimEnd('0円');}

Question 37

Shouldn't Trim() work instead of TrimEnd()? Even better, I think you can save a lot of bytes by using s[0] as the output var and using return new string(s[0],0,i) where i is the index of the last code character. That idea may require two for loops instead of the foreach, I'll think about it more and try to write actual code later today.

Question 38

Trim() will trim from the start as well, which I believe wouldn't be valid. I also was originally doing the loading into s[0] and I had int i; outside of the loop (to reuse it in the return) which I believe ultimately added bytes

Question 39

Pyth, 11 bytes

PhceCSMCQ\#

A program that takes input of a list of strings on STDIN and prints a string.

Try it online

How it works

PhceCSMCQ\# Program. Input: Q
 CQ Transpose Q
 SM Sort each element of that lexicographically
 C Transpose that
 e Yield the last element of that, giving the program ending with ' #' and some
 parts of the comments
 c \# Split that on the character '#'
 h Yield the first element of that, giving the program with a trailing space
P All but the last element of that, removing the trailing space
 Implicitly print

Question 40

sed, 126 bytes

:a;N;$!ba;s,#[^\n]*\n,#,g;s,^,#,;:;/#[^ ]/{/^# /s,^# *,,;t;H;s,#.,#,g}
t;/#[^ ]/!{H;s,#.,#,g};t;g;s,\n#(.)[^\n]*,1,円g;s,...,,ドル

Requires a newline at the end of the input.
I'm sure I can golf this a little more, but I'm just happy it works for now.

Question 41

Perl 6, 39 bytes

{[Zmax](@_».comb).join.split(' #')[0]}

Translation of the Python solution by Dennis.
Takes input as a list of strings, and returns a string.

(try it online)

Question 42

Jelly, 27 bytes

żḟ€" ;€" Ḣ€
i€"#’©ḣ@"ç/ḣ®ṪṖ

Test it at TryItOnline

Uses the strictest spec - the extra space before the comment character is removed at the cost of a byte.

Input is a list of strings.

Question 43

@Erik the Golfer - maybe so, but did you see the crushing he gave me here?

Question 44

Ruby, 77 bytes

puts File.readlines("stack.txt").join('').gsub(/\s{1}#.*\n/,'').gsub(/\s/,'')

Question 45

Hardcoding an input filename is not an acceptable method of input.

Question 46

@Mego, where can I find the rules of what's "acceptable"?

Question 47

meta.codegolf.stackexchange.com/q/2447/45941

Question 48

TSQL, (削除) 216 (削除ここまで) 175 bytes

Golfed:

DECLARE @ varchar(max)=
'hello #Line one
 #Line two
 world! #Line three'
DECLARE @i INT=1,@j INT=0WHILE @i<LEN(@)SELECT @=stuff(@,@j+1,len(x),x),@j=iif(x=char(10),0,@j+1),@i+=1FROM(SELECT ltrim(substring(@,@i,1))x)x PRINT LEFT(@,patindex('%_#%',@))

Ungolfed:

DECLARE @ varchar(max)=
'hello #Line one
 #Line two
 world! #Line three'
DECLARE @i INT=1,@j INT=0
WHILE @i<LEN(@)
 SELECT @=stuff(@,@j+1,len(x),x),@j=iif(x=char(10),0,@j+1),@i+=1
 FROM(SELECT ltrim(substring(@,@i,1))x)x
PRINT LEFT(@,patindex('%_#%',@))

Fiddle

Question 49

Dyalog APL, 22 bytes

Inspiration.

(⎕UCS ̄2↓⍳∘35↑⊢)⌈⌿∘⎕UCS

(

⎕UCS character representation of

̄2↓ all but the last two of

⍳∘35↑ up until the position of the first 35 ("#"), in that which is outside the parenthesis, taken from

⊢ that which is outside the parenthesis

) namely...

⌈⌿ the columnar maximums

∘ of

⎕UCS the Unicode values

TryAPL online!

Question 50

How many bytes?

Dennis Dennis 212k41 gold badges379 silver badges829 bronze badges · Accepted Answer · 2016-09-13 02:25:43Z

18

\$\begingroup\$

Jelly, (削除) 8 (削除ここまで) 7 bytes

»/ṣ"#ḢṖ

Try it online!

How it works

»/ṣ"#ḢṖ Main link. Argument: A (array of strings)
»/ Reduce the columns of A by maximum.
 Since the space is the lowest printable ASCII characters, this returns the
 non-space character (if any) of each column.
 ṣ"# Split the result at occurrences of '#'.
 Ḣ Head; extract the first chunk, i.e., everything before the (first) '#'.
 Ṗ Pop; remove the trailing space.

Share

Improve this answer

edited Sep 13, 2016 at 2:53

answered Sep 13, 2016 at 2:25

Dennis's user avatar

Dennis Dennis

212k41 gold badges379 silver badges829 bronze badges

\$\endgroup\$

5

2

\$\begingroup\$ That is just ...wow. \$\endgroup\$

Jonathan Allan
– Jonathan Allan

2016年09月13日 02:26:36 +00:00
Commented Sep 13, 2016 at 2:26
3

\$\begingroup\$ I am so jelly right now. \$\endgroup\$

MonkeyZeus
– MonkeyZeus

2016年09月13日 13:49:39 +00:00
Commented Sep 13, 2016 at 13:49
\$\begingroup\$ How do you even hack that into your phone? \$\endgroup\$

simbabque
– simbabque

2016年09月13日 16:14:06 +00:00
Commented Sep 13, 2016 at 16:14
2

\$\begingroup\$ @simbabque Patience and a lot of copy-pasting. \$\endgroup\$

Dennis
– Dennis

2016年09月13日 16:49:59 +00:00
Commented Sep 13, 2016 at 16:49
\$\begingroup\$ I'm always putting using a 9-iron, maybe it's time I learned how to use a putter when on the green... \$\endgroup\$

Magic Octopus Urn
– Magic Octopus Urn

2016年09月13日 20:19:23 +00:00
Commented Sep 13, 2016 at 20:19

Add a comment |

Stack Exchange Network

Parse the comments out of my esoteric code

The Challenge:

Examples:

19 Answers 19

Jelly, (削除) 8 (削除ここまで) 7 bytes

How it works

Python 2, (削除) 48 (削除ここまで) 43 bytes

JavaScript (ES6), (削除) 97 (削除ここまで) (削除) 75 (削除ここまで) 60 bytes

Perl, (削除) 35 (削除ここまで) (削除) 34 (削除ここまで) 32 bytes

Python 2, 187 bytes

Ruby, 63 bytes

CJam, 12 bytes

Explanation

J, 30 bytes

Commented and explained

Test case

Javascript (ES6), 63 bytes

Retina, 32 bytes

Pyke, (削除) 15 (削除ここまで) 10 bytes

C# (削除) 157 (削除ここまで) 122 Bytes

Pyth, 11 bytes

sed, 126 bytes

Perl 6, 39 bytes

Jelly, 27 bytes

Ruby, 77 bytes

TSQL, (削除) 216 (削除ここまで) 175 bytes

Dyalog APL, 22 bytes

Your Answer

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Hot Network Questions

Parse the comments out of my esoteric code

The Challenge:

Examples:

19 Answers 19

Jelly, (削除) 8 (削除ここまで) 7 bytes

How it works

Python 2, (削除) 48 (削除ここまで) 43 bytes

JavaScript (ES6), (削除) 97 (削除ここまで) (削除) 75 (削除ここまで) 60 bytes

Perl, (削除) 35 (削除ここまで) (削除) 34 (削除ここまで) 32 bytes

Python 2, 187 bytes

Ruby, 63 bytes

CJam, 12 bytes

Explanation

J, 30 bytes

Commented and explained

Test case

Javascript (ES6), 63 bytes

Retina, 32 bytes

Pyke, (削除) 15 (削除ここまで) 10 bytes

C# (削除) 157 (削除ここまで) 122 Bytes

Pyth, 11 bytes

sed, 126 bytes

Perl 6, 39 bytes

Jelly, 27 bytes

Ruby, 77 bytes

TSQL, (削除) 216 (削除ここまで) 175 bytes

Dyalog APL, 22 bytes

Your Answer

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Post as a guest

Post as a guest

Linked

Related

Hot Network Questions