Reference · Vectors

vec.transpose

vec.transpose(list | null) -> list

What it does

Rows turned into columns: for a list of rows of one length, a list of the columns, each the items at one position of every row. The items can be anything, not only numbers; they are moved, not converted.

Examples

print(vec.transpose([[1, 2, 3], [4, 5, 6]]))print(vec.transpose([["a", 1], ["b", 2]]))

[[1, 4], [2, 5], [3, 6]][["a", "b"], [1, 2]]

Edge cases

• One row of n items gives n rows of one item, and back.
• The empty list, or null, gives the empty list; so does one empty row, since there are no columns.
• Transposing twice gives the original.
• Items keep their values and types: strings, null and booleans travel as they are.

print(vec.transpose([[1, 2, 3]]), vec.transpose([[1], [2], [3]]))print(vec.transpose([]), vec.transpose(null), vec.transpose([[]]))print(vec.transpose(vec.transpose([[1, 2], [3, 4]])))print(vec.transpose([["a", 1], [null, true]]))

[[1], [2], [3]] [[1, 2, 3]][] [] [][[1, 2], [3, 4]][["a", null], [1, true]]

Errors

Rows of different lengths, or a row that is not a list, are runtime errors, not error values.

print(vec.transpose([[1, 2], [3]]))

line 1: `vec.transpose`: row 1 has 1 items, row 0 has 2

print(vec.transpose([1, 2]))

line 1: `vec.transpose` expects a list of rows, but row 0 is int

Chaining

Column totals of a table of rows, and pairs of lists turned into a list of pairs:

let table = [[1, 2], [3, 4], [5, 6]]print(table | vec.transpose | map(sum))print(vec.transpose([["x", "y"], [10, 20]]))

[9, 12][["x", 10], ["y", 20]]

See also

vec.matmul, vec.column, zip, map

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