Keithley 2657A

Section 6: Instrument programming Model 2657A High Power System SourceMeter® Instrument Reference Manual
6-22 2657A-901-01 Rev. B/December 2012
For loops
There are two variations of for statements supported in Lua: numeric and generic.
In a for loop, the loop expressions are evaluated once, before the loop starts.
Example: Numeric for
list = {"One", "Two", "Three", "Four", "Five", "Six"}
---------- For loop -----------
print("Counting from one to three:")
for element = 1, 3 do
print(element, list[element])
end
print("Counting from one to four, in steps of two:")
for element = 1, 4, 2 do
print(element, list[element])
end
The numeric for loop repeats a block of code while a control variable runs through an
arithmetic progression.
Output:
Counting from one to three:
1.00000e+00 One
2.00000e+00 Two
3.00000e+00 Three
Counting from one to four, in steps of two:
1.00000e+00 One
3.00000e+00 Three
Example: Generic for
days = {"Sunday",
"Monday", "Tuesday",
"Wednesday", "Thursday",
"Friday", "Saturday"}
for i, v in ipairs(days) do
print(days[i], i, v)
end
The generic for statement works by using functions called iterators. On each iteration, the
iterator function is called to produce a new value, stopping when this new value is nil.
Output:
Sunday 1.00000e+00 Sunday
Monday 2.00000e+00 Monday
Tuesday 3.00000e+00 Tuesday
Wednesday 4.00000e+00 Wednesday
Thursday 5.00000e+00 Thursday
Friday 6.00000e+00 Friday
Saturday 7.00000e+00 Saturday
NOTE