Python and GeoGebra numbers

A Number is a dynamic value which can be used in calculations and, e.g., as an x or y coordinate of a geometric object. If the Number’s value changes, any geometric objects depending on that Number will update.

The current numeric value (as a Python float) of a Number can be get or set via its value property.

Example

import time

x = Number(-3.0)

p_static = Point(x.value, 1.0)
p_dynamic = Point(x, 2.0)

for _ in range(600):
    x.value += 0.01
    time.sleep(0)

Running this code will show

p_static: a stationary point at (-3, 1), and
p_dynamic: a point which moves smoothly from (-3, 2) to (3, 2).

GeoGeobra also shows the two points differently, because the one referred to by p_static is independent whereas the one referred to by p_dynamic is not.

Calculations with `Number`s

If you use a Number in a calculation, the result is another Number. This works in a similar way to a spreadsheet formula which refers to another cell — when a cell’s value changes, all dependent cells update.

Example

import time

x = Number(-3.0)
x2 = 2.0 * x

p1 = Point(x, 1.0)
p2 = Point(x2, 2.0)
k1 = Line(p1, p2)

for _ in range(600):
    x.value += 0.01
    time.sleep(0)