Section 10: Instrument programming
Series 3700A System Switch/Multimeter Reference Manual
10-26
3700AS-901-01 Rev. D/June 2018
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.
The output you get from these examples may vary depending on the data format settings of the
instrument.
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 One
2 Two
3 Three
Counting from one to four, in steps of two:
1 One
3 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 Sunday
Monday 2 Monday
Tuesday 3 Tuesday
Wednesday 4 Wednesday
Thursday 5 Thursday
Friday 6 Friday
Saturday 7 Saturday
