代码及如下
– Example 7 – Keywords.
– Lua reserved words are: and, break, do, else, elseif,
– end, false, for, function, if, in, local, nil, not, or,
– repeat, return, then, true, until, while.
– Keywords cannot be used for variable names,
– ‘and’ is a keyword, but AND is not, so it is a legal variable name.
AND=3
print(AND)
-------- Output ------
3
Press 'Enter' key for next example
– Example 8 – Strings.
a=“single ‘quoted’ string and double “quoted” string inside”
b=‘single ‘quoted’ string and double “quoted” string inside’
c= [[ multiple line
with ‘single’
and “double” quoted strings inside.]]
print(a)
print(b)
print©
-------- Output ------
single ‘quoted’ string and double “quoted” string inside
single ‘quoted’ string and double “quoted” string inside
multiple line
with ‘single’
and “double” quoted strings inside.
Press 'Enter' key for next example
– Example 9 – Assignments.
– Multiple assignments are valid.
– var1,var2=var3,var4
a,b,c,d,e = 1, 2, “three”, “four”, 5
print(a,b,c,d,e)
-------- Output ------
1 2 three four 5
Press ‘Enter’ key for next example
– Example 10 – More Assignments.
– Multiple assignments allows one line to swap two variables.
print(a,b)
a,b=b,a
print(a,b)
-------- Output ------
1 2
2 1
Press ‘Enter’ key for next example
– Example 11 – Numbers.
– Multiple assignment showing different number formats.
– Two dots (…) are used to concatenate strings (or a
– string and a number).
a,b,c,d,e = 1, 1.123, 1E9, -123, .0008
print(“a=”…a, “b=”…b, “c=”…c, “d=”…d, “e=”…e)
-------- Output ------
a=1 b=1.123 c=1000000000 d=-123 e=0.0008
Press ‘Enter’ key for next example
– Example 12 – More Output.
– More writing output.
print “Hello from Lua!”
print(“Hello from Lua!”)
-------- Output ------
Hello from Lua!
Hello from Lua!
Press ‘Enter’ key for next example
– Example 13 – More Output.
– io.write writes to stdout but without new line.
io.write(“Hello from Lua!”)
io.write(“Hello from Lua!”)
– Use an empty print to write a single new line.
print()
-------- Output ------
Hello from Lua!Hello from Lua!
Press ‘Enter’ key for next example
– Example 14 – Tables.
– Simple table creation.
a={} – {} creates an empty table
b={1,2,3} – creates a table containing numbers 1,2,3
c={“a”,“b”,“c”} – creates a table containing strings a,b,c
print(a,b,c) – tables don’t print directly, we’ll get back to this!!
-------- Output ------
table: 00BB6AE0 table: 00BB6BF8 table: 00BB6C20
Press ‘Enter’ key for next example
– Example 15 – More Tables.
– Associate index style.
address={} – empty address
address.Street=“Wyman Street”
address.StreetNumber=360
address.AptNumber=“2a”
address.City=“Watertown”
address.State=“Vermont”
address.Country=“USA”
print(address.StreetNumber, address[“AptNumber”])
-------- Output ------
360 2a
Press ‘Enter’ key for next example
– Example 17 – if else statement.
b=“happy”
if b==“sad” then
print(“b is sad”)
else
print(“b is not sad”)
end
-------- Output ------
b is not sad
Press ‘Enter’ key for next example
– Example 18 – if elseif else statement
c=3
if c1 then
print(“c is 1”)
elseif c2 then
print(“c is 2”)
else
print("c isn’t 1 or 2, c is "…tostring©)
end
-------- Output ------
c isn’t 1 or 2, c is 3
Press ‘Enter’ key for next example
– Example 19 – Conditional assignment.
– value = test and x or y
a=1
b=(a==1) and “one” or “not one”
print(b)
– is equivalent to
a=1
if a==1 then
b = “one”
else
b = “not one”
end
print(b)
-------- Output ------
one
one
Press ‘Enter’ key for next example
– Example 20 – while statement.
a=1
while a~=5 do – Lua uses ~= to mean not equal
a=a+1
io.write(a…" ")
end
-------- Output ------
2 3 4 5
Press ‘Enter’ key for next example
– Example 21 – repeat until statement.
a=0
repeat
a=a+1
print(a)
until a==5
-------- Output ------
1
2
3
4
5
Press ‘Enter’ key for next example
– Example 22 – for statement.
– Numeric iteration form.
– Count from 1 to 4 by 1.
for a=1,4 do io.write(a) end
print()
– Count from 1 to 6 by 3.
for a=1,6,3 do io.write(a) end
-------- Output ------
1234
14
Press ‘Enter’ key for next example
– Example 23 – More for statement.
– Sequential iteration form.
for key,value in pairs({1,2,3,4}) do print(key, value) end
-------- Output ------
1 1
2 2
3 3
4 4
Press ‘Enter’ key for next example
– Example 24 – Printing tables.
– Simple way to print tables.
a={1,2,3,4,“five”,“elephant”, “mouse”}
for i,v in pairs(a) do print(i,v) end
-------- Output ------
1 1
2 2
3 3
4 4
5 five
6 elephant
7 mouse
Press ‘Enter’ key for next example
– Example 25 – break statement.
– break is used to exit a loop.
a=0
while true do
a=a+1
if a==10 then
break
end
end
print(a)
-------- Output ------
10
Press ‘Enter’ key for next example