CodeGolf - Ignore the noise #1

Question

Instructions

Barry is a not so good backend developer in charge of a small API that should give you information about purchases made in a client's shop. However, he hasn't done a great job and your boss tells you to fix it client-side instead. Ideally you should receive comma-separated values such as 927,2,45,90 which correspond to something like item_id,item_amount,unit_price,total

In this first puzzle we only care about item_id and item_amount but we need the other fields in place to present the problem. Barry sometimes gets things mixed up and returns noise as part of the output, he also gets the order wrong, returning noise, noise, unit_price, total, item_id, item_amount.

Your Task

You need to store in a map (or similar structure) the pairs of item_id and item_amount regardless of whether Barry returns them correctly or not and print each element in a new line in the least number of characters possible. (Storing is not mandatory, we just care about the output)

Sample input (mixed correct and messy formats)

103,2,50,100
106,1,900,900
459,40,150,300,67,2
4,20,30,6000

In other words input will be either a,b,x,x or x,x,x,x,a,b where what we care about is a & b. You need to provide code assuming we have a variable called G (or any other name) with all the lines of csv.

Sample output

103,2
106,1
67,2 //This one was messy
4,20

Tolerance

There is a certain margin for tolerance when it comes to the answer. Answers in similar formats but adhering to the correct values, will also be accepted. Formats like [a,b],(a,b) or {a,b} are valid, but a,b is preferred.

Although the first puzzle had mixed acceptance due to the fact that it was easy and fast to solve, I also felt that some people liked that too. So I'm going to continue making quickgolfs for now

Answer 1

Pyth, 10 bytes

FNG<.<N4 2

Try it online: Pyth Compiler/Executor

(The first 4 chars =G.Q reads all the data and stores it in G)

Explanation

FNG              for row N in G:
    .<N4            cyclic leftshift by 4
   <     2          print the first two elements

Answer 2

Perl, 24

perl -pe's/(\d+,){4}|,\d+,\d+$//'

Example:

perl -pe's/(\d+,){4}|,\d+,\d+$//' <in
103,2
106,1
67,2
4,20

Answer 3

Python 3, 123 76 72 62 bytes

I'm a newcomer, gotta start somewhere...

 for l in G:
  d=l.rstrip().split(',');x=[0,4][len(d)>5];print(d[x:x+2])

With xnor's and DLosc's suggestions (62 bytes):

for l in G:d=l.rstrip().split(',');print(d[4*(len(d)>5):][:2])

Answer 4

Sed, 32 bytes

s/,/=/4
s/.*=//
s/,/:/2
s/:.*//

This deletes everything up to the 4th comma if there is one. Then it deletes everything from the 2nd comma (which may have previously been 6th).

And I even managed to right-justify!

Answer 5

Javascript, 44 bytes

Assuming input in variable G.

Edit: I just realized, this looks a lot like nutki's perl solution.

alert(G.replace(/(\d+,){4}|,\d+,\d+$/gm,''))

Snippet Demo:

function run(){
    G = input.value;
    /* start solution */
    alert(G.replace(/(\d+,){4}|,\d+,\d+$/gm,''))
    /* end solution */
}

<textarea id="input" cols="25" rows="6">103,2,50,100
106,1,900,900
459,40,150,300,67,2
4,20,30,6000</textarea><br />
<button id="run" onclick="run();">Run</button>

Answer 6

Scala, 68 bytes

G.map(_.split(",")).map(x=>println((x++x).slice(4,6).mkString(",")))

-- MrBones

Scala, 46 70 bytes

Edit: Print out the result

for{l<-G;r=l.split(",");x=(r++r).slice(4,6).mkString(",")}{println(x)}

Demo

Answer 7

CJam, 18 15 14 bytes

r{',/4m<2<pr}h

Try it online in the CJam interpreter.

How it works

r      e# Read a whitespace separated token from STDIN.
{      e# Do-while loop:
  ',/  e#    Split at commas.
  4m<  e#    Rotate the resulting array 4 units to the left.
  2<   e#    Discard everything but the first 2 elements.
  p    e#    Print the array.
  r    e#    Read a whitespace separated token from STDIN.
}h     e# If the token is a nonempty string, repeat the loop.

Answer 8

POSIX shell, 30 bytes

Assuming POSIX sed and cut are present:

sed 's/.*/&,&/'|cut -d, -f5,6

Duplicates the line, leaving the data of interest ready to be extracted from fields 5 and 6.

Answer 9

Javascript, 117 112 99 95 84 76 71 bytes

for(r of G.split('\n'))s=r.split(','),console.log(s[t=s[4]?4:0],s[t+1])

JS Fiddle

Answer 10

Pip, 12 + 1 = 13 bytes

Uses the -l flag, which gives the output as space-separated lists of numbers on each line.*

_@[4 5]Mg^',

Explanation:

• The list of numbers is expected in g. Since g is normally initialized from the command-line arguments, you can also put the input there for the same results.
• ^', splits (each string in) the list on commas.
• M maps a function to each element in the result.
• _@[4 5] defines a lambda function. The argument to the function is represented by _; @[4 5] returns a list of its 4th and 5th elements. If the list has six elements, these will be the last two. If it has four, the indices wrap around, and so the result is the first two. (E.g. "abcd"@4 == "abcd"@0 == "a".)
• We now have a list of lists, like [[103 2] [106 1] [67 2]], which is auto-printed at the end of the program. The -l flag joins each sub-list on space and then the whole thing on newline, so the result is as follows:

C:\>pip.py -le "_@[4 5]Mg^'," 103,2,50,100 106,1,900,900 459,40,150,300,67,2
103 2
106 1
67 2

_{* Currently. I may change this behavior, but I'm still planning to have some flag that does the same thing.}

Answer 11

Perl, 37

@c=/(\d+,\d+)/g;$_=@c>2?$c[2]:$c[0]

35 characters +2 for -p and -l. I'm not sure if there is an approach in Perl that would beat @nutki's solution, but I figured I'd post this idea I had anyway.

Run with:

cat input.txt | perl -ple'@c=/(\d+,\d+)/g;$_=@c>2?$c[2]:$c[0]'

Answer 12

bash, 54

while IFS=, read {a..f};do echo ${e:-$a},${f:-$b};done

Answer 13

C, 95 bytes

f(a,b,c,d){scanf("%d,%d,%*d,%*d,%d,%d",&a,&b,&c,&d)>2?printf("%d,%d",c,d):printf("%d,%d",a,b);}

The code is simple. Here is the ungolfed version:

f(a,b,c,d){                                    //Four int variables
    scanf("%d,%d,%*d,%*d,%d,%d",&a,&b,&c,&d)>2 //Scan input
        ?                                      //If scanf returned a value > 2
        printf("%d,%d",c,d)                    //Print last two values
        :                                      //else 
        printf("%d,%d",a,b);                   //Print first two values
}

Test it here

Answer 14

Ruby, 53

G.each_line{|x|g=x.split',';p[g[4]||g[0],g[5]||g[1]]}

or is good.