Binary strings: Difference between revisions

J's literal data type supports arbitrary binary data (strings are binary strings by default). J's semantics are pass by value (with garbage collection) with a minor exception (mapped files).

* Example binary string creation

<lang j> name=: ''</lang>

* Example binary string deletion (removing all references to a string allows it to be deleted, in this case we give the name a numeric value to replace its prior string value):

<lang j> name=: 0</lang>

* Example binary string assignment

* Example binary string comparison

* Example binary string cloning and copying

<lang j> name1= 'example'

name2= name1</lang>

Though, technically, its the internal reference which is cloned, not the internal representation of the value. But operations which modify strings are copy on write, so this distinction is not visible without going outside the language.

* Example check if a binary string is empty

* Example apppend a byte to a binary string

<lang j> string=: 'example'

byte=: DEL

string=: string,byte</lang>

* Extract a substring from a binary string

Note also: given an integer n, the corresponding byte value may be obtained by indexing into <code>a.</code> which is the ordered array of all bytes.:

<lang j> n{a.</lang>

Thus, the binary string containing bytes with numeric values 1 0 255 can be obtained this way:

<lang j>1 0 255{a.</lang>