Most Preferred Input Format

Question

If I were to pass your program an integer array as input, what format would you prefer?

I understand that this question is primarily opinion-based, but it is also incredibly useful information for those of us who want to write challenges that appeal to the largest number of people.

Answer 1

Comma, Semicolon separated

1,2,3;4,5,6;7,8,9

The logical separation of comma-delimited lists (in the English language) is semicolons. And this format makes it easy (and roughly equal between languages) to parse, split on ; and ,. Additionally, it is easy to add more dimensions: simply add another delimiter.

Answer 2

.CSV

Terminated with a newline.

1,1,1\n2,2,2\n3,3,3\n

You can see the RFC at https://www.rfc-editor.org/rfc/rfc4180, but it looks barbaric. There is no "official" standard.

Answer 3

JSON

For example, this 3 by 3 array of integers:

[[1,2,3],[4,5,6],[7,8,9]]

See format at http://json.org/

Answer 4

Newline-separated

1
2
3
4
5
6
7
8
9

This is the most generic format, and the easiest to parse in any programming language. Not all programming languages can easily split strings on a delimiter, but all of them can easily read a single line of input from stdin. The program just needs to read the number of lines it expects in a loop, and add each number to an array.

This format does not directly support nested arrays. If you want to represent a 2D matrix, add two more lines before the list with the number of rows followed by the number of columns, e.g. 3 and 3.

Answer 5

Comma-Separated, Curly-Brace Wrapped

For example, this 3 by 3 array of integers:

{{1,1,1},{2,2,2},{3,3,3}}

Answer 6

Having the answer dictate how an array is to be entered would be preferable since some have integrated parsers for certain formats while other don't.

Since it isn't here yet I'll add LISP lists and vectors (called proper arrays in other languages):

(1 2 3 4 5)  ; list
#(1 2 3 4 5) ; vector

You can easily nest them:

((1 2 3) (4 5 6))    ; list in list
#(#(1 2 3) #(4 5 6)) ; vector in vector (compatible)
#2A((1 2 3) (4 5 6)) ; 2 dimentional vector in CL

Answer 7

Space-separated, square-bracket wrapped

[[1 2 3][4 5 6][7 8 9]]

This is the format which GolfScript can evaluate most easily, so naturally GolfScript users will prefer it.

Answer 8

Space separated:

1 2 3 4 5 6 7 8 9

which would give the 3x3

1 4 7
2 5 8
3 6 9

(at least it will if you're a column-major programmer).