Reference · stzList

FindDuplicates()

The position of every 2nd+ occurrence of each duplicated item.

also written: FindDuplications · FindDuplicatedItems

Basic examples (2)

Softanza

o1 = new stzList([ 5, 7, 5, 5, 4, 7, 1 ])
? o1.Duplicates()
? o1.FindDuplicates()

Output

run on 2026-10-02 04:22 inside the library at commit 0e72e2e2c; taken from 258_managing_duplicated_items_check_errros.ring(opens in a new tab)

Softanza

o1 = new stzList([ "a", "ab", "b", 1:3, "a", "ab", "abc", "b", "bc", 1:3,"c" ])
? o1.FindDuplicates()
? @@( o1.ItemsAtPositions( o1.FindDuplicates() ) )
? @@( o1.Duplicates() ) + NL
? @@( o1.DuplicatesZ() )

Output

5
6
8
10

[ "a", "ab", "b", [ 1, 2, 3 ] ]
[ "a", "ab", "b", [ 1, 2, 3 ] ]

[ [ "a", [ 5 ] ], [ "ab", [ 6 ] ], [ "b", [ 8 ] ], [ [ 1, 2, 3 ], [ 10 ] ] ]

run on 2026-10-02 04:22 inside the library at commit 0e72e2e2c; taken from 266_findduplicates.ring(opens in a new tab)

Scope (3)

Softanza

o1 = new stzList([ 5, 7, 5, 5, 4, 7 ])
? o1.ContainsDuplicates()
? o1.HowManyDuplicates()
? @@( o1.FindDuplicates() )
? @@( o1.DuplicatesZ() ) # Or DuplicatesAndTheirPositions()
o1.RemoveDuplicates()
? @@( o1.Content() )

Output

1
3
[ 3, 4, 6 ]
[ [ 5, [ 3, 4 ] ], [ 7, [ 6 ] ] ]
[ 5, 7, 4 ]

run on 2026-10-02 04:22 inside the library at commit 0e72e2e2c; taken from 243_containsduplicates.ring(opens in a new tab)

Softanza

o1 = new stzList([ "_", "ONE", "_", "_", "TWO", "_", "THREE", "*", "*" ])
? o1.ContainsDuplicates()
? @@( o1.FindDuplicates() )
? @@( o1.Duplicates() )
? @@( o1.DuplicatesZ() ) # Or DuplicatesAndTheirPositions()
o1.RemoveDuplicates()
? @@( o1.Content() )

Output

1
[ 3, 4, 6, 9 ]
[ "_", "*" ]
[ [ "_", [ 3, 4, 6 ] ], [ "*", [ 9 ] ] ]
[ "_", "ONE", "TWO", "THREE", "*" ]

run on 2026-10-02 04:22 inside the library at commit 0e72e2e2c; taken from 234_containsduplicates.ring(opens in a new tab)

Softanza

o1 = new stzList([
		"*", "*4", "*4*", "*4*3", "*4*34",
		"4", "4*", "4*3", "4*34", "*", "*3",
		"*34", "3", "34", "4"
	])
# numberofduplicates example 1
? @@( o1.NumberOfDuplicates() )
# numberofduplicates example 2
? @@( o1.FindDuplicates() )
# numberofduplicates example 3
? @@( o1.Duplicates() )
# numberofduplicates example 4
? @@( o1.DuplicatesZ() )

Output

2
[ 10, 15 ]
[ "*", "4" ]
[ [ "*", [ 10 ] ], [ "4", [ 15 ] ] ]

run on 2026-10-02 04:22 inside the library at commit 0e72e2e2c; taken from 167_numberofduplicates.ring(opens in a new tab)

The extensions of this method

Each extension, and whether it exists for this method; an extension that exists combines with the others (FindSTCS).

Extension

Exists

What it adds · The names

yes

does what the method does, then returns the object, so the call can be chained · FindDuplicatesQ

chains on the next, more specific type of object (the Q ladder)

QQQ

chains on the most specific type of object (the Q ladder)

QRT

returns the result as an object of the requested type

yes

takes a case-sensitivity flag · FindDuplicatesCS, FindDuplicatesCSXT

takes the position to start from (StartingAt)

takes bounds that are included (IncludingBounds)

yes

the extended form: more parameters than the base method · FindDuplicatesXT, FindDuplicationsXT, FindDuplicatesCSXT

XTT

yet another extension: a further extended form, after XT

includes the position in what it returns

returns positions as sections, [start, end]

selects by a condition

selects by a condition, with the expressive keywords (@NextItem, @PreviousItem...)

takes a direction, forward or backward (Directional)

takes a function (the condition or the update is given as a function); the forms document also uses F for the future form, which defers the action

Many

works on a collection of items instead of one (the plural form)

Except

takes exceptions, what to leave out (the exceptional form)

returns the result without duplication

Every example is a test file of the library, run inside the library for this page; only those whose output kept every promise their file wrote are shown.

FindDuplicates()

Basic examples (2)

Scope (3)

The extensions of this method

See also