Tektronix KEITHLEY SourceMeter 2606B Reference Manual page 321

Section 14: Instrument programming
Variable types
Variables can be one of the following types.
Variable types and values
Variable type returned
"nil"
"boolean"
"number"
"string"
"function"
"table"
"userdata"
"thread"
To determine the type of a variable, you can call the type() function, as shown in the
examples below.
The output you get from these examples may vary depending on the data format that is set.
Example: Nil
x = nil
print(x, type(x))
Example: Boolean
y = false
print(y, type(y))
Example: String and number
x = "123"
print(x, type(x))
x = x + 7
print(x, type(x))
14-16
Model 2606B System SourceMeter® Instrument Reference Manual
Value
not declared
true or false
number
sequence of words or
characters
a block of code
an array
variables
line of execution
nil
false
123
Adding a number to x forces its type to number.
130
Notes
The type of the value nil, whose main property is
to be different from any other value; usually it
represents the absence of a useful value.
Boolean is the type of the values false and true.
In Lua, both nil and false make a condition
false; any other value makes it true.
All numbers are real numbers; there is no
distinction between integers and floating-point
numbers.
Functions perform a task or compute and return
values.
New tables are created with { } braces.
For example:
{1, 2, 3.00e0}
Allows arbitrary program data to be stored in Lua
variables.
nil
boolean
string
number
2606B-901-01 Rev. C November 2021