lua入门案例实战123DIY
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
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– 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.
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– 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
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– 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
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– 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
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– Example 12 – More Output.
– More writing output.
print “Hello from Lua!”
print(“Hello from Lua!”)
-------- Output ------
Hello from Lua!
Hello from Lua!
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– 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!
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– 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
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– 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
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– 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
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– 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
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– 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
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– 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
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– Example 21 – repeat until statement.
a=0
repeat
a=a+1
print(a)
until a==5
-------- Output ------
1
2
3
4
5
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– 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
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– 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
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– 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
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– 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
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