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2600AS-901-01 Rev. B / September 2008 Return to Section Topics 19-5

Series 2600A System SourceMeter® Instruments Reference Manual Section 19: Remote Commands

Tables/arrays

TSL makes extensive use of the data type “table,” which is essentially a very flexible array-like

data type.

Define a table:

atable = {1, 2, 3, 4}

Print it:

-- Tables are indexed starting at one, NOT zero.

i = 1

-- atable[index] is true if there is an element at that index; nil is returned

-- otherwise. 0 does NOT evaluate to false - only nil does.

while atable[i] do

-- Index into table using a number.

print(atable[i])

i = i + 1

end

Output of code above:

Tables can be indexed using element names instead of numeric indices. Since functions are first-

class variables, tables can be used to create "pseudo-classes." Classes are often used in object-

oriented programming.

Below is a table used to create a circle pseudo-class. It has 3 elements:

clr: A string containing the color of the circle.

diam: A number containing the diameter of the circle.

setdiam: A function, or method, used to change the diameter.

circle = {clr = "red", diam = 1, setdiam = function(d)

circle["diam"] = d end}

-- Index using a string; print the clr property.

print(circle["clr"])

-- Index using a string; print the diam property.

print(circle["diam"])

-- Change the diam element by calling setdiam method.

circle["setdiam"](2)

-- circle["diam"] is the same as circle.diam; simpler syntax.

print(circle.diam)

-- Change the diameter of the circle again.

circle.setdiam(3)

-- Print diam property again using simple syntax.

print(circle.diam)

Output of code above:

red

Keithley 2600a series User Manual

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