How can I check to see that a spreadsheet (comma delimited) contains only numbers?

[johnsold]

Checking for zeros is probably an order of magnitude faster than testing the strings. As crossrulz said, you need to be absolutely certain that zero is never a valid or possible value.

Lynn

[ijustlovemath]

The sensor is used as a controller for a biological system. The system dies if the sensor value is zero, so it should go into disaster mode if they're legitimate.