# Scala algorithm: Reshape a matrix

Published

## Algorithm goal

Turn an m-by-n matrix into an n-by-m matrix, retaining the order of the elements. For example:

1 | 2 | 3 |

4 | 5 | 6 |

Becomes:

1 | 2 |

3 | 4 |

5 | 6 |

## Test cases in Scala

```
assert(reshapeMatrix(Vector.empty) == Vector.empty)
assert(reshapeMatrix(Vector(Vector(1))) == Vector(Vector(1)))
assert(reshapeMatrix(Vector(Vector(1, 2))) == Vector(Vector(1), Vector(2)))
assert(
reshapeMatrix(Vector(Vector(1, 2), Vector(3, 4))) ==
Vector(Vector(1, 2), Vector(3, 4))
)
assert(
reshapeMatrix(Vector(Vector(1, 2, 3), Vector(4, 5, 6))) ==
Vector(Vector(1, 2), Vector(3, 4), Vector(5, 6))
)
```

## Algorithm in Scala

3 lines of Scala (version 2.13), showing how concise Scala can be!

## Explanation

In Scala this is straightforward: flatten the whole matrix, and then group the elements into chunks of length of the height of the matrix (.grouped). (this is Â© from www.scala-algorithms.com)

## Scala concepts & Hints

### View

The

`.view`

syntax creates a structure that mirrors another structure, until "forced" by an eager operation like .toList, .foreach, .forall, .count.