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Reference · stzString

FindDupSecutiveSubString()

Same as FindDupSecutiveSubStringCS: FindDupSecutiveSubString: positions where the substring at i+1 equals the substring of the same length ending at i (i.e. back-to-back identical substrings). Returns the start positions of the second copy in each consecutive pair. ENGINE-BACKED (StzEngineStringFindDupSecutiveSubStringCS): start of the second copy in each back-to-back identical-substring pair. Retires the O(len) Haro while-loop (2 EngineSlice round-trips per step). pCaseSensitive=0 compares the substrings case-insensitively.

Basic examples (1)

Softanza
oAB  = new stzString("ab")
big  = new stzString( oAB.Repeated(1000000) )
oaA = new stzString("aA")
mBig = new stzString( oaA.Repeated(500000) )  # "aAaA..." 1,000,000 chars
# FindDupSecutiveCharsCS(1) is 0 (a <> A)
? len(mBig.FindDupSecutiveCharsCS(1))
# FindDupSecutiveCharsCS(0) is 999,999 (a == A folded)
? len(mBig.FindDupSecutiveCharsCS(0))
oAB2 = new stzString("ab")
bigab = new stzString( oAB2.Repeated(100000) )  # "abab..." 200,000 chars
# FindDupSecutiveSubString('ab') is 99,999
? len(bigab.FindDupSecutiveSubString("ab"))
Output
0
999999
99999

run on 2026-10-02 04:24 inside the library at commit 0e72e2e2c; taken from 999_engine_string_millions_narrated.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
Q
no
does what the method does, then returns the object, so the call can be chained
QQ
no
chains on the next, more specific type of object (the Q ladder)
QQQ
no
chains on the most specific type of object (the Q ladder)
QRT
no
returns the result as an object of the requested type
CS
yes
takes a case-sensitivity flag · FindDupSecutiveSubStringCS
ST
no
takes the position to start from (StartingAt)
IB
no
takes bounds that are included (IncludingBounds)
XT
no
the extended form: more parameters than the base method
XTT
no
yet another extension: a further extended form, after XT
Z
no
includes the position in what it returns
ZZ
yes
returns positions as sections, [start, end] · FindDupSecutiveSubStringZZ
W
no
selects by a condition
WF
no
selects by a condition, with the expressive keywords (@NextItem, @PreviousItem...)
D
no
takes a direction, forward or backward (Directional)
F
no
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
no
works on a collection of items instead of one (the plural form)
Except
no
takes exceptions, what to leave out (the exceptional form)
U
no
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.

See also