Match coordinates with their values

Question

Given 3 input items, a list of coordinate pairs, a 2D string, and a single-character string, output whether the character at each coordinate of the 2D string is equal to the single character. You can take the input in any order and the coordinates may be 1-indexed.

You may take the 2D string as a 2D list, a list of lines, or a 2D string.

Example: (0,0), "#_\n__", "#" -> True

The string is

#_
__

The char at the coordinate (0,0) (from the top left) is #. This is equal to the third input item, #, so you output True (or any truthy value)

Example: [(0,0), (1,1)], "#_\n_#", "#" -> True

The string is

#_
_#

The characters at the coordinates of (0,0) and (1,1) are both #, so the output is true.

The output is only true iff every coordinate matches a hash. Not every hash has to have a matching coordinate though. If there are no occurrences of the single char (# in some of the test cases) in the 2D string, the output is still just falsy.

You can assume the coordinates will always be within the bounds of the 2D string.

More test cases: (I put the single char second for ease of readability)

[(0,0), (2,1), (3,0)], #

#_##
#_##

True


[(0,0), (1,1), (3,0)], #

#_##
#_##

False (1,1 is not a hash)



[(1,1)], a

#a##
#a##

True


[(4, 0), (3, 0), (2, 0), (1, 0), (0, 0), (0, 1), (0, 2), (0, 3), (1, 3), (2, 3), (2, 2), (3, 2), (4, 2), (4, 3)], ' '


 ####
 #   
   # 

True

Note the last test case uses spaces as the single char string, and hashes around the spaces.

Related. (inverse of this challenge)

Answer 1

Dyalog APL, 8 bytes

Prompts for list of coordinate pairs (row,column), then 2D array, then character.

∧/⎕=⎕[⎕]

[⎕] prompt for coordinates and use them to scatter pick from

⎕ prompted input (2D array)

= compare the selected elements to

⎕ input (the character)

∧/ check if all are true (AND-reduction)

Test cases (⎕IO←0 to match examples, but this is not necessary):

First example

Second example

Third example

Fourth example

Fifth example

Answer 2

Python, 39 bytes

Takes the inputs:

1. a list of (x, y) integer coordinates
2. b list of strings
3. c single character string

---

lambda a,b,c:{b[y][x]for x,y in a}=={c}

Answer 3

Octave, 45 38 29 bytes

@(A,B,C)A(1+B*[rows(A);1])==C

A function that takes a 2D array of chars as A and coordinates(0 based) B as a two column matrix of [col row] and the matching character as C. The two element coordinates(using matrix multiplication) converted to linear index.

Note: Previous answer that made use of sparse matrix was wrong.

Other Contributors:

Stewie Griffin for saving 5 bytes noting that [0 1 0] can be regarded as false value!!

Luis Mendo for saving 2 bytes that ~0 == true and notification about sparse matrix.

Try it Online

Answer 4

JavaScript (ES6), 37 bytes

Takes the inputs:

1. a array of [x, y] integer coordinates
2. s array of strings
3. c single character string

---

(a,s,c)=>a.every(([x,y])=>s[y][x]==c)

Answer 5

Mathematica, 28 bytes

#3~Extract~#~MatchQ~{#2...}&

1-indexed. Due to how arrays are structured in Mathematica, the input coordinates must be reversed (i.e. (row, column))

Usage

#3~Extract~#~MatchQ~{#2...}&[{{1, 1}, {2, 3}, {1, 4}}, "#", {{"#", "_", "#", "#"}, {"#", "_", "#", "#"}}]

True

Answer 6

Perl 6, 41 40 bytes

->\c,\h,\n{all map {n eq h[.[0];.[1]]},c}

->$_,\h,\n{all .map:{n eq h[.[0];.[1]]}}

Expects the 2D string as a 2D list.

Thanks to b2gills for -1 byte.

Answer 7

Haskell, 27 bytes

s!c=all(\(x,y)->s!!y!!x==c)

Usage example: ( ["#_##","#_##"] ! '#' ) [(0,0), (2,1), (3,0)] -> True.

Answer 8

C#, 80 77 bytes

Saved 3 bytes, thanks to pinkfloydx33

a=>b=>c=>{foreach(var i in a){if(b[i[0]][i[1]]!=c){return 1<0;}}return 1>0;};

a is the pairs of coordinate, b is the list of lines, and c is the single-character string.

Answer 9

Jelly, 10 bytes

ịṪ⁸ịḢð€Q⁼⁵

This only works as a full program. Input order is indices, string array, singleton string.

Try it online!

How it works

ịṪ⁸ịḢð€Q⁼⁵  Main link.
            Left argument:  P (array of coordinate pairs)
            Right argument: S (array of strings)
            Third argument: C (singleton string)

     ð€     Combine the links to the left into a dyadic chain and call it with each
            p = (x, y) in P as left argument and S as the right one.
ị             Unindex; retrieve the strings of S at indices x and y.
 Ṫ            Tail; yield s, the string of S at index y.
  ⁸ị          Unindex; retrieve the characters of s at indices x and y.
    Ḣ         Head; yield the character of s at index x.
       Q    Unique; deduplicate the resulting string/array of characters.
        ⁼⁵  Compare the result with the third argument.

Answer 10

Haskell, 72 63 bytes

c [] _ _ =1<2;c ((f,s):t) m n |n/=lines m!!s!!f=1>2|1>0=c t m n

Input of c [(0,0), (1,0), (3,0)] "#_##\n#_##" '#' Outputs False

Input c [(4, 0), (3, 0), (2, 0), (1, 0), (0, 0), (0, 1), (0, 2), (0, 3), (1, 3), (2, 3), (2, 2), (3, 2), (4, 2), (4, 3)] " \n ####\n # \n # " ' '

Output True

UnGolfed

checkfunc :: [(Int,Int)] -> String -> Char -> Bool
checkfunc [] _ _ = True
checkfunc (x:xs) string char | char /= ((lines string)!!(snd x))!!(fst x)= False  -- Checks first coordinates and returns False if no match
                             | otherwise = checkfunc xs string char --Otherwise iterate over remaining coordinate pairs

Answer 11

Scala, 68 bytes

def f(l:(Int,Int)*)(s:String*)(c:Char)=l forall{x=>s(x._2)(x._1)==c}

Answer 12

Clojure, 39 bytes

#(apply = %3(map(fn[[x y]]((%2 y)x))%))

Example (string input is a vec of vec of characters):

(def f #(apply = %3(map(fn[[x y]]((%2 y)x))%)))
(f [[0 0] [1 1] [3 0]] (mapv vec ["#_##" "#_##"]) \#)