StringPosition

StringPosition["string","sub"]

gives a list of the starting and ending character positions at which "sub" appears as a substring of "string".

StringPosition["string",patt]

gives all positions at which substrings matching the general string expression patt appear in "string".

StringPosition["string",patt,n]

includes only the first n occurrences of patt.

StringPosition["string",{patt1,patt2,}]

gives positions of all the patti.

StringPosition[{s1,s2,},p]

gives the list of results for each of the si.

StringPosition[patt]

represents an operator form of StringPosition that can be applied to an expression.

Details and Options

Examples

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Basic Examples  (3)

Find the starting and ending positions at which "XYZ" occurs in a string:

Find where any pairs of identical characters occur:

Use the operator form of StringPosition:

Scope  (7)

StringPosition gives substring positions in the form used by functions like StringTake:

Find the position of the first occurrence of "XYZ":

StringPosition by default includes overlaps:

Use Overlaps->False to exclude overlaps:

Find the position of a subsequence within a DNA sequence:

Use a wild card in the pattern found in a given bio sequence:

The "N" is a degenerate letter and is not a wild card except in bio sequences:

Additional wraparound matches may be found in circular bio sequences:

Match only literal degenerate letter occurrences using Verbatim:

Options  (4)

IgnoreCase  (2)

Treat "a" and "A" as the same:

Treat "a" and "A" as different:

Find successive identical characters independent of case:

Overlaps  (2)

StringPosition by default includes overlaps:

By default, StringPosition only includes one substring starting at any given position:

With Overlaps->All, it includes all substrings:

Applications  (2)

Find positions of pairs of identical letters in a concatenation sequence:

Find an analogous curve for triples:

Find the positions of the word "president" in the US Constitution:

Properties & Relations  (2)

Use StringTake to extract substrings found by StringPosition:

StringCases by default excludes overlaps:

Use StringReplacePart to replace at positions found by StringPosition:

Possible Issues  (1)

Lists of string patterns in StringPosition are sometimes not the same as pattern alternatives:

Wolfram Research (1991), StringPosition, Wolfram Language function, https://reference.wolfram.com/language/ref/StringPosition.html (updated 2020).

Text

Wolfram Research (1991), StringPosition, Wolfram Language function, https://reference.wolfram.com/language/ref/StringPosition.html (updated 2020).

BibTeX

@misc{reference.wolfram_2021_stringposition, author="Wolfram Research", title="{StringPosition}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/StringPosition.html}", note=[Accessed: 01-August-2021 ]}

BibLaTeX

@online{reference.wolfram_2021_stringposition, organization={Wolfram Research}, title={StringPosition}, year={2020}, url={https://reference.wolfram.com/language/ref/StringPosition.html}, note=[Accessed: 01-August-2021 ]}

CMS

Wolfram Language. 1991. "StringPosition." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/StringPosition.html.

APA

Wolfram Language. (1991). StringPosition. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/StringPosition.html