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Lua for Pythoners - Lists

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[code=lua]
-- Using Lua standard libraries and Penlight (http://luaforge.net/frs/?group_id=450)
-- List catalog: http://www.java2s.com/Code/Python/List/CatalogList.htm
package.path=package.path..';./?/init.lua'
require 'pl'
stringx.import()
function string:totable()
    return seq.copy(seq.map (function (x) return self:at(x) end, seq.range(1,#self)))
end
function List:__mul (n)
    res = List()
    for i=1,n do
        res:extend (self)
    end
    return res
end

print ("===List")
print ("==List Declaration")
print ("=Lists can be written as a list of comma-separated values (items) between square brackets.")

a = List {'spam', 'eggs', 100, 1234}
print (a)

print ("==List Append")
print ("=Adding elements to lists")
li = List {'a', 'b', 'mpilgrim', 'z', 'example'}
li:insert (2, "new")                                
print (li)

print ("=Append element to a list")
scores = List {"1","2","3"}

-- add a score
io.write("What score did you get?: ")
score = tonumber(io.read())
scores:append (score)

-- list high-score table
for score in scores:iter() do
       print (score)
end

print ("=List append(x)")
a = {66.25, 333, 333, 1, 1234.5}

table.insert (a, 333)
print (unpack(a))

print ("=List: The Difference Between Extend and Append")
li = List {'a', 'b', 'c'}
li:extend {'d', 'e', 'f'}
print (li)

print (#li)

print (li[#li])

li = List {'a', 'b', 'c'}
li:append (List {'d', 'e', 'f'})

print (li)

print (#li)

print (li[#li])

print ("==List Intersect")
print ("=Define function to intersect Strings and lists")
function intersect(seq1, seq2)
    if type(seq1) == 'string' then
        seq1 = seq1:totable()
    end
    if type(seq2) == 'string' then
        seq2 = seq2:totable()
    end

res = {}                          -- start empty
    for x in seq.iter(seq1) do        -- scan seq1
        if tablex.find(seq2,x) then   -- common item?
            table.insert(res,x)       -- add to end
        end
    end
    return res
end
s1 = "SPAM"
s2 = "SCAM"

print (unpack(intersect(s1, s2)))                   -- strings

s1 = {1,2,3,4,5}
s2 = {3,4,5,6,7}

print (unpack(intersect(s1, s2)))                   -- list

print ("=Function to intersect two lists")
function intersect(seq1, seq2)
    res = {}                          -- start empty
    for x in seq.iter(seq1) do        -- scan seq1
        if tablex.find(seq2,x) then   -- common item?
            table.insert(res,x)       -- add to end
        end
    end
    return res
end

x = intersect({1, 2, 3}, {1, 4}) -- mixed types
print (unpack(x))                -- saved result object

print ("==List Reverse")
print ("=List reverse(): Reverse the elements of the list, in place")
a = List {66.25, 333, 333, 1, 1234.5}
a:reverse()
print (a)

print ("=Sort and reverse elements in list")
scores = List {"1","2","3"}

scores:sort()

for score in scores:iter() do
   print (score)
end

scores:reverse()        -- want the highest number first

-- list high-score table
for score in scores:iter() do
   print (score)
end

print ("==Variables in List")
print ("=Variables in a list")
X = {1, 2, 3}
L = {'a', X, 'b'}            -- embed references to X's object
D = {x=X, y=2}

X[1] = 'surprise'            -- changes all three references!

print (pretty.write(L))

print (pretty.write(D))

print ("==List Assign")
print ("=Assign list to a list item")
L = List {'Already', 'got', 'one'}
L:slice_assign(2,nil,{})
print (L)

L[1] = List()
print (L)

print ("==List Filter")
print ("=Introducing List Filtering")

li = List {"a", "mpilgrim", "foo", "b", "c", "b", "d", "d"}

print (li:filter (function(x) return #x>1 end))

print (li:filter (function(x) return x~='b' end))

print (li:filter (function(x) return li:count(x)==1 end))

print ("==List concatenation")
print ("=Concatenate two lists")
inventory = List {"sword", "armor", "shield", "healing potion"}
chest = List {"gold", "gems"}
print ("You find a chest which contains:")
print (chest)
print ("You add the contents of the chest to your inventory.")
inventory = inventory .. chest
print ("Your inventory is now:")
print (inventory)

print ("==List In")
print ("=Use in to check Membership ")
permissions = 'rw'
print (permissions:find ('w') and true or false)
print (permissions:find ('x') and true or false)

users = {'mlh', 'foo', 'bar'}
print (tablex.find(users, 'foo') and true or false)

print ("==List Loop")
print ("=List for iteration")
for _,x in pairs({1, 2, 3}) do io.write(x..' ') end      -- iteration

print ("=To iterate over the indices of a sequence, combine range() and len()")
a = {'Mary', 'had', 'a', 'little', 'lamb'}

for i,v in pairs(a) do
     print (i, v)
end

print ("==List Sort")
print ("=Sort elements in a list")

L = List {'spam', 'Spam', 'SPAM!'}

print (L:append('please'))                -- append method call

L:sort()                          -- sort list items ('S' < 'e')
print (L)

print ("==List Compare")
print ("=List equivalent?, same object?")
L1 = List {1, List {'a', 3}}         -- same value, unique objects
L2 = List {1, List {'a', 3}}
print (L1 == L2, rawequal(L1, L2))         -- equivalent?, same object?

print ("=Same Object or identical content")
S1 = 'spam'
S2 = 'spam'
print (S1 == S2, rawequal(S1, S2))

S1 = 'a longer string'
S2 = 'a longer string'
print (S1 == S2, rawequal(S1, S2))

print ("=List: less,equal,greater: tuple of results")
-- Penlight doesn't implement list compare

print ("==List Comprehensive")
print ("=List comprehensions: for and tuple")
C = comprehension.new()
print(unpack(C "x..y for x for y" (('spam'):totable(), ('SPAM'):totable())))
print(unpack(C "List {x,y} for x=0,4 for y=0,4 if x%2==0 if y%2==1" ()))

print ("=Find Prime numbers using list")
C = comprehension.new()
noprimes = C "j for i=2,8 for j=i*2,50,i" ()
primes = C "x for x=2,50 if not tablex.find(_1,x)" (noprimes)
print (unpack(primes))

print ("=List Comprehensions in buildConnectionString, Step by Step")
params = {["Key 1"]="value 1", ["key 2"]="value 2", ["key 3"]="value 3", ["key 4"]="value 4"} 
print (unpack(tablex.pairmap (function(k,v) return k end, params)))
print (unpack(tablex.pairmap (function(k,v) return v end, params)))
print (unpack(tablex.pairmap (function(k,v) return ("%s=%s"):format(k, v) end, params)))

print ("==List Indexing")
print ("=List offset: start at zero, negative and slicing")
L = List {'spam', 'Spam', 'SPAM!'}
print (L[3])                               -- offsets start at zero
print (L:slice(-2,-2)[1])                  -- negative: count from the right
print (L:slice(2))                         -- slicing fetches sections

print ("=Searching a list for an integer.")
-- Create a list of even integers 0 to 198
aList = List {}
for i=0,199,2 do aList:append (i) end

io.write("Enter integer search key: ")
searchKey = tonumber(io.read ())

if aList:contains (searchKey) then
   print ("Found at index:", aList:index (searchKey))
else
   print ("Value not found")
end

print ("=Reference index in a list in Python.")
foo = List {42, 'www.java2s.com', function(x) return x^2 end, List {47, '11'}}
print (foo)
print (foo[4])
print (foo[3](3))

foo[4][1] = 99
print (foo)
for i in foo:iter() do
     print (i, "--", type(i))
end

print ("==List Remove")
print ("=List Delete: delete one item and delete an entire section")
L = List {'SPAM!', 'eat', 'more', 'please'}
L:remove(1)                       -- delete one item
print (L)

L:chop(2)                         -- delete an entire section
print (L)

print ("=Deleting List Elements")
li = List {'a', 'b', 'new', 'mpilgrim', 'z', 'example', 'new', 'two', 'elements'}

print (li:remove_value("z"))
print (li)

li:remove_value("new")
print (li)

li:remove_value("z")

print (li)

print ("==List Count")
print ("=List count(x)")
-- Return the number of times x appears in the list. 
a = List {66.25, 333, 333, 1, 1234.5}
print (a:count(333))

print ("==List Empty/List repetition")
print ("=Empty list multiply/List repetition")
L = List {0} * 100
print (L)

print ("==List Pop")
print ("=Using Lists as Stacks")
stack = List {3, 4, 5}
stack:push(6)
stack:push(7)
print (stack)

stack:pop()

print (stack)
print (stack:pop())
print (stack:pop())
print (stack)

print ("==List Two Dimension")
print ("=Nested list: two dimensions")
matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}

print (unpack(matrix[2]))
print (matrix[2][2])
print (matrix[3][1])

print ("=Check a user name and PIN code")
database = List {
    List {'A', '1234'},
    List {'B', '4242'},
    List {'C', '7524'},
    List {'D', '9843'}
}

io.write ("User name: ")
username = io.read()
io.write ("PIN code: ")
pin = io.read()
if database:contains(List {username, pin}) then print ("Access granted") end

print ("==Return List")
print ("=A function that returns a list of the numbers of the Fibonacci series")
function fib2(n) -- return Fibonacci series up to n
     -- Return a list containing the Fibonacci series up to n.
     result = List {}
     a, b = 0, 1
     while b < n do
         result:append(b)    -- see below
         a, b = b, a+b
     end
     return result
end

f100 = fib2(100)    -- call it
print (f100)        -- write the result

[/code]

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