Given a string representing a matrix of numbers, return the rows and columns of that matrix.
So given a string with embedded newlines like:
9 8 7
5 3 2
6 6 7
representing this matrix:
0 1 2
|---------
0 | 9 8 7
1 | 5 3 2
2 | 6 6 7
your code should be able to spit out:
The rows for our example matrix:
And its columns:
To run the tests, run the command busted
from within the exercise directory.
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local Matrix = require('matrix')
describe('matrix', function()
it('should allow rows to be extracted', function()
local matrix = Matrix('1 2 3\n4 5 6\n7 8 9')
assert.same({ 1, 2, 3 }, matrix.row(1))
assert.same({ 4, 5, 6 }, matrix.row(2))
assert.same({ 7, 8, 9 }, matrix.row(3))
end)
it('should allow columns to be extracted', function()
local matrix = Matrix('1 2 3\n4 5 6\n7 8 9')
assert.same({ 1, 4, 7 }, matrix.column(1))
assert.same({ 2, 5, 8 }, matrix.column(2))
assert.same({ 3, 6, 9 }, matrix.column(3))
end)
it('should support values of varying sizes', function()
local matrix = Matrix('1 2 3\n4 12345 6\n7 8 9')
assert.same({ 4, 12345, 6 }, matrix.row(2))
assert.same({ 2, 12345, 8 }, matrix.column(2))
end)
it('should support matrices of varying sizes', function()
local matrix = Matrix('1 2\n3 4\n5 6')
assert.same({ 3, 4 }, matrix.row(2))
assert.same({ 2, 4, 6 }, matrix.column(2))
end)
end)
local function Matrix(input)
local row_table = {}
for line in input:gmatch('[%d ]+') do
table.insert(row_table, line)
end
local function row(index)
local result = {}
local row_string = row_table[index]
for w in row_table[index]:gmatch('%d+') do
table.insert(result, tonumber(w))
end
return result
end
local function column(index)
local rows
local result = {}
for i = 1, #row_table do
rows = row(i)
table.insert(result, rows[index])
end
return result
end
return { row = row, column = column }
end
return Matrix
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Community comments
Hmm, looks like an unused variable on line 10. Looks good otherwise.
looks straight forward - good job