Ground GPIO off?

[Shastarocks]

I lately took apart a old vcr that didn't work and salvaged the LCD display, and it fits perfectly into the breadboard. The problem is I need to flash it very quickly to display something. In order to do that I will need to turn off the ground GPIO pens to put letters or numbers.
The image shows where the found pins are and how you use each pin to display each text block. If I want to display more then one block, I have to rapidly switch from one of the negative pins and and a few positive, to another negative and a few positive.. all I need is part of a python script to turn on and off the ground pins. Like GPIO.setup ([ground pins #],GPIO.out and GPIO.output([ground#],True)

[B.Goode]

The pins designated as Ground on the 40-way header of an RPi are not controlled by the gpio circuitry of the RPi and cannot be manipulated under program control. The Ground pins are always Ground.

[pcmanbob]

Hi.

If you want to switch Ground you can use a ULN2803A Darlington Transistor Array. :- http://www.ti.com/lit/ds/symlink/uln2803a.pdf
Each chip has 8 channels, that you can drive directly from the GPIO pins, only the logic is reversed , so a high input will give you a ground on the corresponding output, but that should not be a problem its a simple matter to code it that way.