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Wolfram Language & System Documentation Center
StringJoin
  • See Also
    • Join
    • StringApply
    • StringRiffle
    • StringRepeat
    • StringExpression
    • Row
    • Characters
    • StringInsert
    • StringReplacePart
    • StringPartition
    • StringTemplate
    • FileNameJoin
  • Related Guides
    • String Operations
    • String Manipulation
    • Character Operations
    • Text Generation
    • Wolfram Language Syntax
    • Biomolecular Sequences
  • Tech Notes
    • Operations on Strings
    • Characters in Strings
    • See Also
      • Join
      • StringApply
      • StringRiffle
      • StringRepeat
      • StringExpression
      • Row
      • Characters
      • StringInsert
      • StringReplacePart
      • StringPartition
      • StringTemplate
      • FileNameJoin
    • Related Guides
      • String Operations
      • String Manipulation
      • Character Operations
      • Text Generation
      • Wolfram Language Syntax
      • Biomolecular Sequences
    • Tech Notes
      • Operations on Strings
      • Characters in Strings

"s1"<>"s2"<>…, StringJoin["s1","s2",…], or StringJoin[{"s1","s2",…}]

yields a string consisting of a concatenation of the si.

Details
Details and Options Details and Options
Background & Context
Examples  
Basic Examples  
Scope  
Applications  
Properties & Relations  
Possible Issues  
See Also
Tech Notes
Related Guides
Related Links
History
Cite this Page
BUILT-IN SYMBOL
  • See Also
    • Join
    • StringApply
    • StringRiffle
    • StringRepeat
    • StringExpression
    • Row
    • Characters
    • StringInsert
    • StringReplacePart
    • StringPartition
    • StringTemplate
    • FileNameJoin
  • Related Guides
    • String Operations
    • String Manipulation
    • Character Operations
    • Text Generation
    • Wolfram Language Syntax
    • Biomolecular Sequences
  • Tech Notes
    • Operations on Strings
    • Characters in Strings
    • See Also
      • Join
      • StringApply
      • StringRiffle
      • StringRepeat
      • StringExpression
      • Row
      • Characters
      • StringInsert
      • StringReplacePart
      • StringPartition
      • StringTemplate
      • FileNameJoin
    • Related Guides
      • String Operations
      • String Manipulation
      • Character Operations
      • Text Generation
      • Wolfram Language Syntax
      • Biomolecular Sequences
    • Tech Notes
      • Operations on Strings
      • Characters in Strings

StringJoin

"s1"<>"s2"<>…, StringJoin["s1","s2",…], or StringJoin[{"s1","s2",…}]

yields a string consisting of a concatenation of the si.

Details

  • StringJoin has attribute Flat.
  • StringJoin[BioSequence["type","seq"]…] will concatenate biomolecular sequences of the same type.

Background & Context

  • StringJoin["s1","s2",…], which may also be written using the shorthand notation "s1"<>"s2"<>⋯, returns the string formed by the concatenation of strings "si". StringJoin ignores lists at any level in its arguments and so may be applied to nested list structures without the need for flattening. While StringJoin works only with explicit valid strings, ToString can often be used to convert non-string expressions into string form.
  • StringJoin is related to a number of other symbols. In practice, StringJoin is an inverse of Characters, in the sense that StringJoin[Characters["string"]] and Characters[StringJoin[{"s","t","r","i","n","g"}]] return "string" and {"s","t","r","i","n","g"}, respectively. StringJoin is a String analog and/or generalization of the qualitatively similar functions Join, Append, Prepend, Catenate and JoinAcross. In particular, "s1"<>"s0" prepends and "s0"<>"s1" appends a string "s1" to a given string "s0". StringJoin should not be confused with StringExpression ("s1"~~"s2"~~⋯), which is used to specify string patterns. StringJoin is also related to and commonly used in conjunction with StringRiffle, StringRepeat, StringInsert, StringReplacePart and StringPartition.

Examples

open all close all

Basic Examples  (2)

Join strings:

Wolfram Language code: "abcd" <> "ABCD" <> "xyz"

Use InputForm to show string quotes:

Wolfram Language code: InputForm[%]

All lists are ignored:

Wolfram Language code: StringJoin[{{"AB", "CD"}, "XY"}]

Scope  (4)

StringJoin works with special characters:

Wolfram Language code: "αβγ" <> "⊕⊗" <> " ↵"

Join strings, with a newline in between:

Wolfram Language code: "one" <> " " <> "two"

StringJoin preserves formatting information embedded in strings:

Wolfram Language code: "red" <> "blue"

Join biomolecular sequences:

Wolfram Language code: StringJoin[BioSequence["DNA", "A"], BioSequence["DNA", "C"]]

Applications  (4)

Iteratively join a string to its reverse:

Wolfram Language code: NestList[# <> StringReverse[#]&, "AB", 5]

Find trigrams in a string:

Wolfram Language code: data = Partition[Characters["aabcaabc"], 3, 1]
Wolfram Language code: StringJoin /@ data

Join a list of words, after inserting spaces in between:

Wolfram Language code: Riffle[{"dog", "cat", "sheep", "cow"}, " "]
Wolfram Language code: StringJoin[%]

Create a Champernowne number:

Wolfram Language code: ToExpression[StringJoin["0.", ToString /@ Range[30]]]

Properties & Relations  (1)

StringJoin acts as a kind of inverse to Characters:

Wolfram Language code: Characters["abcdefg"]
Wolfram Language code: StringJoin[%]

Possible Issues  (1)

StringJoin works only with explicit strings:

Wolfram Language code: "item " <> 456

Use ToString to convert to a string:

Wolfram Language code: "item " <> ToString[456]

See Also

Join  StringApply  StringRiffle  StringRepeat  StringExpression  Row  Characters  StringInsert  StringReplacePart  StringPartition  StringTemplate  FileNameJoin

Tech Notes

    ▪
  • Operations on Strings
  • ▪
  • Characters in Strings

Related Guides

    ▪
  • String Operations
  • ▪
  • String Manipulation
  • ▪
  • Character Operations
  • ▪
  • Text Generation
  • ▪
  • Wolfram Language Syntax
  • ▪
  • Biomolecular Sequences

Related Links

  • Fast Introduction for Programmers: Strings
  • An Elementary Introduction to the Wolfram Language : Strings and Text
  • An Elementary Introduction to the Wolfram Language : String Patterns and Templates
  • NKS|Online  (A New Kind of Science)

History

Introduced in 1988 (1.0) | Updated in 2020 (12.2)

Wolfram Research (1988), StringJoin, Wolfram Language function, https://reference.wolfram.com/language/ref/StringJoin.html (updated 2020).

Text

Wolfram Research (1988), StringJoin, Wolfram Language function, https://reference.wolfram.com/language/ref/StringJoin.html (updated 2020).

CMS

Wolfram Language. 1988. "StringJoin." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/StringJoin.html.

APA

Wolfram Language. (1988). StringJoin. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/StringJoin.html

BibTeX

@misc{reference.wolfram_2026_stringjoin, author="Wolfram Research", title="{StringJoin}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/StringJoin.html}", note=[Accessed: 01-September-2026]}

BibLaTeX

@online{reference.wolfram_2026_stringjoin, organization={Wolfram Research}, title={StringJoin}, year={2020}, url={https://reference.wolfram.com/language/ref/StringJoin.html}, note=[Accessed: 01-September-2026]}

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