entering vectors and +/- sign

[mcjtom]

I can't figure out what's the usefulness of +/- symbol when entering vectors (i.e. if [] brackets are hit, the brackets appear as [x +/-]. What does +/- do inside the brackets?

Cheers!

[Helge Gabert]

Expands and contracts rows/columns, and enables one to traverse large matrices quickly with the arrow keys. Hit - or + when you're on the symbol and you'll see.

[Joe Horn]

(08-09-2014 03:08 PM)Helge Gabert Wrote:  Expands and contracts rows/columns, and enables one to traverse large matrices quickly with the arrow keys. Hit - or + when you're on the symbol and you'll see.

Less well known is the fact that pressing × (multiply) creates a new row or column BEFORE the current one (unlike + which creates it AFTER the current one). It's the only way to insert a new first row or new first column.

[Helge Gabert]

Thanks - - I learned something, too!

[mcjtom]

Thanks!

On somewhat related topic: how do I convert a row (or column matrix) to a vector (i.e. lose double square brackets?

[Eddie W. Shore]

I don't recall seeing a command to convert single-row/column matrices into vectors.

Workaround for a single row matrix:
1. Store the matrix. For example, M0.
2. Execute M0(1).

Example: Starting with [[4,2]]:
M0:= [[4,2]]
M0(1) returns [4,2]

[Joe Horn]

(08-11-2014 10:49 AM)mcjtom Wrote:  On somewhat related topic: how do I convert a row (or column matrix) to a vector (i.e. lose double square brackets?

From the keyboard, just copy it to the edit line, place the cursor anywhere within the single-row matrix, and press Shift 5 (the square-bracket key). Shift 5 toggles between matrix and vector. Very handy.