Arrays: Difference between revisions

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=={{header|Phix}}==

In Phix, sequences are '''it''' - there are no other data structures to learn.

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without any need to worry about memory management issues.

<lang Phix>-- ~~simple one-dimensional arrays:~~

-- simple one-dimensional arrays:

sequence s1 = {0.5, 1, 4.7, 9}, -- length(s1) is now 4

sequence s1 = {0.5, 1, 4.7, 9}, -- length(s1) is now 4

s2 = repeat(0,6), -- s2 is {0,0,0,0,0,0}

s2 = repeat(0,6), -- s2 is {0,0,0,0,0,0}

s3 = tagset(5) -- s3 is {1,2,3,4,5}

s3 = tagset(5) -- s3 is {1,2,3,4,5}

?s1[3] -- displays 4.7 (nb 1-based indexing)

?s1[3] -- displays 4.7 (nb 1-based indexing)

s1[3] = 0 -- replace that 4.7

s1[3] = 0 -- replace that 4.7

s1 &= {5,6} -- length(s1) is now 6 ({0.5,1,0,9,5,6})

s1 &= {5,6} -- length(s1) is now 6 ({0.5,1,0,9,5,6})

s1 = s1[2..5] -- length(s1) is now 4 ({1,0,9,5})

s1 = s1[2..5] -- length(s1) is now 4 ({1,0,9,5})

s1[2..3] = {2,3,4} -- length(s1) is now 5 ({1,2,3,4,5})

s1[2..3] = {2,3,4} -- length(s1) is now 5 ({1,2,3,4,5})

s1 = append(s1,6) -- length(s1) is now 6 ({1,2,3,4,5,6})

s1 = append(s1,6) -- length(s1) is now 6 ({1,2,3,4,5,6})

s1 = prepend(s1,0) -- length(s1) is now 7 ({0,1,2,3,4,5,6})

s1 = prepend(s1,0) -- length(s1) is now 7 ({0,1,2,3,4,5,6})

-- negative subscripts can also be used, counting from the other end, eg

-- negative subscripts can also be used, counting from the other end, eg

s2[-2..-1] = {-2,-1} -- s2 is now {0,0,0,0,-2,-1}

s2[-2..-1] = {-2,-1} -- s2 is now {0,0,0,0,-2,-1}

-- multi dimensional arrays:

-- multi dimensional arrays:

sequence y = {{{1,1},{3,3},{5,5}},

sequence y = {{{1,1},{3,3},{5,5}},

{{0,0},{0,1},{9,1}},

{{0,0},{0,1},{9,1}},

{{1,7},{1,1},{2,2}}}

{{1,7},{1,1},{2,2}}}

-- y[2][3][1] is 9

-- y[2][3][1] is 9

y = repeat(repeat(repeat(0,2),3),3)

y = repeat(repeat(repeat(0,2),3),3)

-- same structure, but all 0s

-- same structure, but all 0s

-- Array of strings:

-- Array of strings:

sequence s = {"Hello", "World", "Phix", "", "Last One"}

sequence s = {"Hello", "World", "Phix", "", "Last One"}

-- s[3] is "Phix"

-- s[3~~][2~~] is ~~'h'~~

-- s[3] is "Phix"

-- s[3][2] is 'h'

-- A Structure:

-- A Structure:

sequence employee = {{"John","Smith"},

sequence employee = {{"John","Smith"},

45000,

27,

45000,

~~185.5}~~

27,

185.5}

-- To simplify access to elements within a structure it is good programming style to define constants that name the various fields, eg:

-- To simplify access to elements within a structure it is good programming style to define constants that name the various fields, eg:

constant SALARY = 2

constant SALARY = 2

-- Array of structures:

-- Array of structures:

sequence employees = {

sequence employees = {

{{"Jane","Adams"}, 47000, 34, 135.5}, -- a[1]

{{"Jane","Adams"}, 47000, 34, 135.5}, -- a[1]

{{"Bill","Jones"}, 57000, 48, 177.2}, -- a[2]

{{"Bill","Jones"}, 57000, 48, 177.2}, -- a[2]

-- .... etc.

}

-- .... etc.

}

-- employees[2][SALARY] is 57000

-- employees[2][SALARY] is 57000

-- A tree can be represented easily, for example after adding "b","c","a" to it you might have:

-- A tree can be represented easily, for example after adding "b","c","a" to it you might have:

sequence tree = {{"b",3,2},

sequence tree = {{"b",3,2},

{"c",0,0},

{"c",0,0},

{"a",0,0}}

{"a",0,0}}

-- ie assuming

-- ie assuming

constant ROOT=1, VALUE=1, LEFT=2, RIGHT=3 -- then

constant ROOT=1, VALUE=1, LEFT=2, RIGHT=3 -- then

-- tree[ROOT][VALUE] is "b"

-- tree[ROOT][~~LEFT~~] is ~~3, and tree[3] is the~~ "a"

-- tree[ROOT][VALUE] is "b"

-- tree[ROOT][~~RIGHT~~] is 2, and tree[2] is the "c"

-- tree[ROOT][LEFT] is 3, and tree[3] is the "a"

-- tree[ROOT][RIGHT] is 2, and tree[2] is the "c"

-- The operations you might use to build such a tree (tests/loops/etc omitted) could be:

-- The operations you might use to build such a tree (tests/loops/etc omitted) could be:

tree = {}

tree = {}

tree = append(tree,{"b",0,0})

tree = append(tree,{"b",0,0})

tree = append(tree,{"c",0,0})

tree = append(tree,{"c",0,0})

tree[1][RIGHT] = length(tree)

tree[1][RIGHT] = length(tree)

tree = append(tree,{"a",0,0})

tree = append(tree,{"a",0,0})

tree[1][LEFT] = length(tree)

tree[1][LEFT] = length(tree)

-- Finally, some tests (recall that we have already output a 4.7):

?s[3]

?tree

?tree[ROOT][VALUE]

employees = append(employees, employee)

?employees[3][SALARY]

?s1

?s2