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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