How to use function to automatically calculate in table?

Questions
1

I want a command to automatically add the first and second columns, and put the result into the third column.

Someting wrong as below:

#let mytable(data) = table(
  columns: 3,
  stroke: 1pt black,
  [X value], [Y value], [X+Y],
  ..data.map((x, y) => [x, y, x + y])
)

#mytable((
  (1, 2),
  (3, 4),
  (5, 6)
))

Maybe I misunderstand the map or something else… How can I do? Thanks!

2

Fixing the function calling syntax like this is the first step:

#let mytable(data) = table(
  columns: 3,
  stroke: 1pt + black,
  [X value], [Y value], [X+Y],
  ..data.map(((x, y)) => [x, y, x + y])
)

That makes

image

Need to use #x to use a variable inside content, and also need to give one content value per table cell. The complete fix:

#let mytable(data) = table(
  columns: 3,
  stroke: 1pt + black,
  [X value], [Y value], [X+Y],
  ..data.map(((x, y)) => ([#x], [#y], [#(x + y)])).flatten()
)

#mytable((
  (1, 2),
  (3, 4),
  (5, 6),
))

Every call to the map(f) function f creates one table row, but in the end the table wants all cells in a single array, so we .flatten() the result.

image

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3

Thanks! But I am still a little currious about why there need two ((x,y)) here? the inner stand for the input (1,2), and the outer one stand for the parameter of this anonymous function?

4

Each element in the data array is itself an array (1, 2) and so on. I guess it’s like this

data.map( ( (x, y) ) => none)
             \_ Unpack first argument into two values.
           \_ The function arguments (of anonymous function)

Without the extra layer of () it would be ambiguous if the unnamed function takes 2 parameters or if it takes 1 and unpacks it.

2 Likes