Array: Difference between revisions

Line 221:

Array

<lang smalltalk>"an array literal (i.e. constant); this is immutable"

<lang smalltalk>"an array literal (i.e. constant); this is immutable.

Array literals are constructed at compile time (thus the following costs effectively nothing)"

a1 := #(10 20 30 40).

"another array literal ~~(i.e. constant); also immutable~~; notice the 5th element being another array"

"another array literal; notice the 5th element being another array"

a2 := #(1.0 20.0 'thirty' true #(5 5 5)).

"a new created array; all 10 elements are nil"

"a new created array; all 10 elements are initially nil"

a4 := Array new:10. ~~"all 10 elements are nil"~~

a4 := Array new:10.

"an new created array with ~~computed~~ elements"

"an new created array with 5 elements computed from expressions (at run time)"

a3 := { 10 . 20 . (a1 at:3) . 40 squared }.</lang>

accessing:

<lang smalltalk>"access by index"

<lang smalltalk>"access by index (notice: in Smalltalk index starts at 1)"

a1 at:2. -> 20

a1 at:index put:100. -> error; immutable

Line 247:

Line 248:

"enumerating"

a1 do:[:e | e printCR ]

a1 do:[:e | e printCR ] -> prints each element

a1 select:[:e | e > 20]. -> #(30 40)

a1 collect:[e | e squared]. -> #(100 400 900 1600)

Line 259:

Line 260:

#(200 300 400) asByteArray -> error raised

(#(65 66 67) collect:#asCharacter) asString -> 'ABC'

#(1 2 3 1 2 3 4) asSet. -> Set(1 2 3 4)

#(1 2 3 1 2 4) asBag. -> Bag(1*2 2*2 3 4)

#(1 2 3 1 2 4) asSortedCollection. -> SortedCollection(1 1 2 2 3 4)

"searching"