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String interpolation

</h1>

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In <a href="Computer_programming" title="Computer programming">computer programming</a>, string interpolation (or variable interpolation, variable substitution, or variable expansion) is the process of evaluating a <a href="String_literal" title="String literal">string literal</a> containing one or more <a href="Form_(document)#Placeholders" title="Form (document)">placeholders</a>, yielding a result in which the placeholders are replaced with their corresponding values. It is a form of simple <a href="Template_processor" title="Template processor">template processing</a><a href="#cite_note-1">[1]</a> or, in formal terms, a form of <a href="Quasi-quotation" title="Quasi-quotation">quasi-quotation</a> (or logic <a href="Substitution_(logic)" title="Substitution (logic)">substitution</a> interpretation). The placeholder may be a variable name, or in some languages an arbitrary expression, in either case evaluated in the current <a href="Scope_(computer_science)" title="Scope (computer science)">context</a>.

String interpolation is an alternative to building string via <a href="Concatenation" title="Concatenation">concatenation</a>, which requires repeat quoting and unquoting;<a href="#cite_note-2">[2]</a> or substituting into a <a href="Printf_format_string" class="mw-redirect" title="Printf format string">printf format string</a>, where the variable is far from where it is used. Compare:

<div class="mw-highlight mw-highlight-lang-ruby mw-content-ltr" dir="ltr"><pre>apples = 4

puts "I have #{apples} apples." # string interpolation

puts "I have " + String(apples) + " apples." # string concatenation

puts "I have %d apples." % apples # format string

</pre></div>

Two types of literal expression are usually offered: one with interpolation enabled, the other without. Non-interpolated strings may also <a href="Escape_sequence" title="Escape sequence">escape sequences</a>, in which case they are termed a <a href="Raw_string" class="mw-redirect" title="Raw string">raw string</a>, though in other cases this is separate, yielding three classes of raw string, non-interpolated (but escaped) string, interpolated (and escaped) string. For example, in Unix shells, single-quoted strings are raw, while double-quoted strings are interpolated. Placeholders are usually represented by a bare or a named <a href="Sigil_(computer_programming)" title="Sigil (computer programming)">sigil</a> (typically <code>$</code> or <code>%</code>), e.g. <code>$apples</code> or <code>%apples</code>, or with braces, e.g. <code>{apples}</code>, sometimes both, e.g. <code>${apples}</code>. In some cases additional formatting specifiers can be used (as in printf), e.g. <code>{apples:3}</code>, and in some cases the formatting specifiers themselves can be interpolated, e.g. <code>{apples:width}</code>. Expansion of the string usually occurs at <a href="Run_time_(program_lifecycle_phase)" class="mw-redirect" title="Run time (program lifecycle phase)">run time</a>.

Language support for string interpolation varies widely. Some languages do not offer string interpolation, instead using concatenation, simple formatting functions, or template libraries. String interpolation is common in many <a href="Programming_language" title="Programming language">programming languages</a> which make heavy use of <a href="String_(computer_science)" title="String (computer science)">string</a> representations of data, such as <a href="Groovy_(programming_language)" class="mw-redirect" title="Groovy (programming language)">Apache Groovy</a>, <a href="Julia_(programming_language)" title="Julia (programming language)">Julia</a>, <a href="Kotlin_(programming_language)" title="Kotlin (programming language)">Kotlin</a>, <a href="Perl" title="Perl">Perl</a>, <a href="PHP" title="PHP">PHP</a>, <a href="Python_(programming_language)" title="Python (programming language)">Python</a>, <a href="Ruby_(programming_language)" title="Ruby (programming language)">Ruby</a>, <a href="Scala_(programming_language)" title="Scala (programming language)">Scala</a>, <a href="Swift_(programming_language)" title="Swift (programming language)">Swift</a>, <a href="Tcl" title="Tcl">Tcl</a> and most <a href="Unix_shell" title="Unix shell">Unix shells</a>.

<div class="mw-heading mw-heading2"><h2 id="Algorithms">Algorithms</h2></div>

There are two main types of variable-expanding algorithms for variable interpolation:<a href="#cite_note-3">[3]</a>

<ol><li>Replace and expand placeholders: creating a new string from the original one, by find–replace operations. Find variable reference (placeholder), replace it by its variable value. This algorithm offers no cache strategy.</li>

<li>Split and join string: splitting the string into an array, merging it with the corresponding array of values, then joining items by concatenation. The split string can be cached for reuse.</li></ol>

<div class="mw-heading mw-heading2"><h2 id="Security_issues">Security issues</h2></div>

String interpolation, like string concatenation, may lead to security problems. If user input data is improperly escaped or filtered, the system will be exposed to <a href="SQL_injection" title="SQL injection">SQL injection</a>, <a href="Script_injection" class="mw-redirect" title="Script injection">script injection</a>, <a href="XML_external_entity_attack" title="XML external entity attack">XML external entity (XXE) injection</a>, and <a href="Cross-site_scripting" title="Cross-site scripting">cross-site scripting</a> (XSS) attacks.<a href="#cite_note-4">[4]</a>

An SQL injection example:

<pre>query = "<code class="mw-highlight mw-highlight-lang-sql mw-content-ltr" style="" dir="ltr">SELECT x, y, z FROM Table WHERE id='$id'</code> "

</pre>

If <code>$id</code> is replaced with "<code>'; <code class="mw-highlight mw-highlight-lang-sql mw-content-ltr" style="" dir="ltr">DELETE FROM Table; SELECT * FROM Table WHERE id='</code></code>", executing this query will wipe out all the data in <code>Table</code>.

<div class="mw-heading mw-heading2"><h2 id="Examples">Examples</h2></div>

/* start https://en.wikipedia.org/ */

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</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="ABAP" title="ABAP">ABAP</a></div>

<div class="mw-highlight mw-highlight-lang-abap mw-content-ltr" dir="ltr"><pre>DATA(apples) = 4.

WRITE |I have { apples } apples|.

</pre></div>The output will be:<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Bash_(Unix_shell)" title="Bash (Unix shell)">Bash (Unix shell)</a></div>

<div class="mw-highlight mw-highlight-lang-bash mw-content-ltr" dir="ltr"><pre>apples=4

echo "I have $apples apples"

# or

echo "I have ${apples} apples"

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Boo_(programming_language)" title="Boo (programming language)">Boo (programming language)</a></div>

<div class="mw-highlight mw-highlight-lang-boo mw-content-ltr" dir="ltr"><pre>apples = 4

print("I have $(apples) apples")

# or

print("I have {0} apples" % apples)

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="C_Sharp_(programming_language)" title="C Sharp (programming language)">C Sharp (programming language)</a></div>

<div class="mw-highlight mw-highlight-lang-csharp mw-content-ltr" dir="ltr"><pre>var apples = 4;

var bananas = 3;

Console.WriteLine($"I have {apples} apples");

Console.WriteLine($"I have {apples + bananas} fruits");

</pre></div><a href="#cite_note-5">[5]</a>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

I have 7 fruits

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="ColdFusion_Markup_Language">ColdFusion Markup Language</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="ColdFusion_Markup_Language" title="ColdFusion Markup Language">ColdFusion Markup Language</a></div>

<a href="ColdFusion_Markup_Language" title="ColdFusion Markup Language">ColdFusion Markup Language</a> (CFML) script syntax:

<div class="mw-highlight mw-highlight-lang-cfc mw-content-ltr" dir="ltr"><pre>apples = 4;

writeOutput("I have #apples# apples");

</pre></div>

Tag syntax:

<cfoutput>I have #apples# apples</cfoutput>

</pre></div>

The output will be:

<pre><samp style="padding-left:0.4em; padding-right:0.4em; color:var( --color-subtle, #666666);">I have 4 apples</samp>

</pre>

<div class="mw-heading mw-heading3"><h3 id="CoffeeScript">CoffeeScript</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="CoffeeScript" title="CoffeeScript">CoffeeScript</a></div>

<div class="mw-highlight mw-highlight-lang-coffeescript mw-content-ltr" dir="ltr"><pre>apples = 4

console.log "I have #{apples} apples"

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Dart_(programming_language)" title="Dart (programming language)">Dart (programming language)</a></div>

<div class="mw-highlight mw-highlight-lang-dart mw-content-ltr" dir="ltr"><pre>int apples = 4, bananas = 3;

print('I have $apples apples.');

print('I have ${apples+bananas} fruits.');

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples.

I have 7 fruits.

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Go_(programming_language)" title="Go (programming language)">Go (programming language)</a></div>

As of 2025, Go does not have string interpolation. There have been some proposals for string interpolation, which have been rejected.<a href="#cite_note-6">[6]</a><a href="#cite_note-7">[7]</a><a href="#cite_note-8">[8]</a>

<div class="mw-heading mw-heading3"><h3 id="Groovy">Groovy</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Groovy_(programming_language)" class="mw-redirect" title="Groovy (programming language)">Groovy (programming language)</a></div>

In groovy, interpolated strings are known as GStrings:<a href="#cite_note-9">[9]</a>

<div class="mw-highlight mw-highlight-lang-groovy mw-content-ltr" dir="ltr"><pre>def quality = "superhero"

final age = 52

def sentence = "A developer is a $quality if he is ${age <= 42 ? 'young' : 'seasoned'}"

println sentence

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>A developer is a superhero if he is seasoned

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Haxe" title="Haxe">Haxe</a></div>

<div class="mw-highlight mw-highlight-lang-haxe mw-content-ltr" dir="ltr"><pre>var apples = 4;

var bananas = 3;

trace('I have $apples apples.');

trace('I have ${apples+bananas} fruits.');

</pre></div>

The output will be:<a href="#cite_note-10">[10]</a>

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples.

I have 7 fruits.

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Java_(programming_language)" title="Java (programming language)">Java (programming language)</a></div>

Java had interpolated strings as a preview feature in Java 21 and Java 22. You could use the constant STR of <a rel="nofollow" class="external text" href="https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/StringTemplate.html">java.lang.StringTemplate</a> directly.<div class="mw-highlight mw-highlight-lang-java mw-content-ltr mw-highlight-lines" dir="ltr"><pre>enum Stage{test,qa,prod}

record Deploy(UUID image, Stage stage){}

var deploy=new Deploy(UUID.randomUUID(), Stage.test)

STR."Installing \{deploy.image()} on Stage \{deploy.stage()} ..."

</pre></div>

They were removed in Java 23 due to design issues.<a href="#cite_note-11">[11]</a>

<div class="mw-heading mw-heading3"><h3 id="JavaScript">JavaScript</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="JavaScript" title="JavaScript">JavaScript</a></div>

<a href="JavaScript" title="JavaScript">JavaScript</a>, as of the <a href="ECMAScript" title="ECMAScript">ECMAScript</a> 2015 (ES6) standard, supports string interpolation using backticks <code>``</code>. This feature is called template literals.<a href="#cite_note-12">[12]</a> Here is an example:

<div class="mw-highlight mw-highlight-lang-javascript mw-content-ltr" dir="ltr"><pre>const apples = 4;

const bananas = 3;

console.log(`I have ${apples} apples`);

console.log(`I have ${apples + bananas} fruits`);

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

I have 7 fruits

</pre></div>

Template literals can also be used for multi-line strings:

<div class="mw-highlight mw-highlight-lang-javascript mw-content-ltr" dir="ltr"><pre>console.log(`This is the first line of text.

This is the second line of text.`);

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>This is the first line of text.

This is the second line of text.

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Julia">Julia</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Julia_(programming_language)" title="Julia (programming language)">Julia (programming language)</a></div>

<div class="mw-highlight mw-highlight-lang-julia mw-content-ltr" dir="ltr"><pre>apples = 4

bananas = 3

print("I have $apples apples and $bananas bananas, making $(apples + bananas) pieces of fruit in total.")

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples and 3 bananas, making 7 pieces of fruit in total.

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Kotlin">Kotlin</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Kotlin_(programming_language)" title="Kotlin (programming language)">Kotlin (programming language)</a></div>

<div class="mw-highlight mw-highlight-lang-kotlin mw-content-ltr" dir="ltr"><pre>val quality = "superhero"

val apples = 4

val bananas = 3

val sentence = "A developer is a $quality. I have ${apples + bananas} fruits"

println(sentence)

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>A developer is a superhero. I have 7 fruits

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Nemerle">Nemerle</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Nemerle" title="Nemerle">Nemerle</a></div>

<div class="mw-highlight mw-highlight-lang-boo mw-content-ltr" dir="ltr"><pre>def apples = 4;

def bananas = 3;

Console.WriteLine($"I have $apples apples.");

</pre></div>

It also supports advanced formatting features, such as:

<div class="mw-highlight mw-highlight-lang-boo mw-content-ltr" dir="ltr"><pre>def fruit = ["apple", "banana"];

Console.WriteLine($<#I have ..$(fruit; "\n"; f => f + "s")#>);

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>apples

bananas

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Nim_(programming_language)" title="Nim (programming language)">Nim (programming language)</a></div>

Nim provides string interpolation via the strutils module.

Formatted string literals inspired by Python F-string are provided via the strformat module,

the strformat macro verifies that the format string is well-formed and well-typed,

and then are expanded into Nim source code at compile-time.

<div class="mw-highlight mw-highlight-lang-nim mw-content-ltr" dir="ltr"><pre>import strutils, strformat

var apples = 4

var bananas = 3

echo "I have $1 apples".format(apples)

echo fmt"I have {apples} apples"

echo fmt"I have {apples + bananas} fruits"

# Multi-line

echo fmt"""

I have

{apples} apples"""

# Debug the formatting

echo fmt"I have {apples=} apples"

# Custom openChar and closeChar characters

echo fmt("I have (apples) {apples}", '(', ')')

# Backslash inside the formatted string literal

echo fmt"""{ "yep\nope" }"""

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

I have 4 apples

I have 7 fruits

I have

4 apples

I have apples=4 apples

I have 4 {apples}

yep

ope

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Nix_package_manager" class="mw-redirect" title="Nix package manager">Nix package manager</a></div>

<div class="mw-highlight mw-highlight-lang-nix mw-content-ltr" dir="ltr"><pre>let numberOfApples = "4";

in "I have ${numberOfApples} apples"

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="ParaSail">ParaSail</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="ParaSail_(programming_language)" title="ParaSail (programming language)">ParaSail (programming language)</a></div>

<div class="mw-highlight mw-highlight-lang-parasail mw-content-ltr" dir="ltr"><pre>const Apples := 4

const Bananas := 3

Println ("I have `(Apples) apples.\n")

Println ("I have `(Apples+Bananas) fruits.\n")

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples.

I have 7 fruits.

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Perl" title="Perl">Perl</a></div>

<div class="mw-highlight mw-highlight-lang-perl mw-content-ltr" dir="ltr"><pre>my $apples = 4;

my $bananas = 3;

print "I have $apples apples.\n";

print "I have @{[$apples+$bananas]} fruit.\n"; # Uses the Perl array (@) interpolation.

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples.

I have 7 fruit.

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="PHP" title="PHP">PHP</a></div>

<div class="mw-highlight mw-highlight-lang-php mw-content-ltr" dir="ltr"><pre><?php

$apples = 5;

$bananas = 3;

echo "There are $apples apples and $bananas bananas.\n";

echo "I have {$apples} apples and {$bananas} bananas.";

</pre></div>The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>There are 5 apples and 3 bananas.

I have 5 apples and 3 bananas.

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Python">Python</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Python_(programming_language)" title="Python (programming language)">Python (programming language)</a></div>

Python supports string interpolation as of version 3.6, referred to as

"formatted string literals" or "f-strings".<a href="#cite_note-13">[13]</a><a href="#cite_note-14">[14]</a><a href="#cite_note-15">[15]</a> Such a literal begins with an <code>f</code> or <code>F</code> before the opening quote, and uses braces for placeholders:

<div class="mw-highlight mw-highlight-lang-python mw-content-ltr" dir="ltr"><pre>num_apples = 4

num_bananas = 3

print(f'I have {num_apples} apples and {num_bananas} bananas')

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples and 3 bananas

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Ruby_/_Crystal">Ruby / Crystal</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Ruby_(programming_language)" title="Ruby (programming language)">Ruby (programming language)</a></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Crystal_(programming_language)" title="Crystal (programming language)">Crystal (programming language)</a></div>

puts "I have #{apples} apples"

# Format string applications for comparison:

puts "I have %s apples" % apples

puts "I have %{a} apples" % {a: apples}

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Rust_(programming_language)" title="Rust (programming language)">Rust (programming language)</a></div>

Rust does not have general string interpolation, but provides similar functionality via macros, referred to as "Captured identifiers in format strings", introduced in version 1.58.0, released 2022-01-13.<a href="#cite_note-16">[16]</a>

Rust provides formatting via the <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/stable/std/fmt/">std::fmt</a> module, which is interfaced with through various macros such as <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/stable/std/macro.format.html">format!</a>, <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/stable/std/macro.write.html">write!</a>, and <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/stable/std/macro.print.html">print!</a>. These macros are converted into Rust source code at compile-time, whereby each argument interacts with a <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/nightly/std/fmt/struct.Formatter.html">formatter</a>. The formatter supports <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/stable/std/fmt/#positional-parameters">positional parameters</a>, <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/stable/std/fmt/#named-parameters">named parameters</a>, <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/stable/std/fmt/#argument-types">argument types</a>, defining various <a rel="nofollow" class="external text" href="https://doc.rust-lang.org/stable/std/fmt/#formatting-traits">formatting traits</a>, and capturing identifiers from the environment.

<div class="mw-highlight mw-highlight-lang-rust mw-content-ltr" dir="ltr"><pre>let (apples, bananas) = (4, 3);

// println! captures the identifiers when formatting: the string itself isn't interpolated by Rust.

println!("There are {apples} apples and {bananas} bananas.");

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>There are 4 apples and 3 bananas.

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Scala">Scala</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Scala_(programming_language)" title="Scala (programming language)">Scala (programming language)</a></div>

<a href="Scala_(programming_language)" title="Scala (programming language)">Scala</a> 2.10+ provides a general facility to allow arbitrary processing of a string literal, and supports string interpolation using the included <code>s</code> and <code>f</code> string interpolators. It is also possible to write custom ones or override the standard ones.

The <code>f</code> interpolator is a compiler macro that rewrites a format string with embedded expressions as an invocation of String.format. It verifies that the format string is well-formed and well-typed.

<div class="mw-heading mw-heading4"><h4 id="The_standard_interpolators">The standard interpolators</h4></div>

Scala 2.10+'s string interpolation allows embedding variable references directly in processed string literals. Here is an example:

<div class="mw-highlight mw-highlight-lang-scala mw-content-ltr" dir="ltr"><pre>val apples = 4

val bananas = 3

//before Scala 2.10

printf("I have %d apples\n", apples)

println("I have %d apples" format apples)

//Scala 2.10+

println(s"I have $apples apples")

println(s"I have ${apples + bananas} fruits")

println(f"I have $apples%d apples")

</pre></div>

The output will be:<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Sciter_(tiscript)">Sciter (tiscript)</h3></div>

In Sciter any function with name starting from $ is considered as interpolating function and so interpolation is customizable and context sensitive:

<div class="mw-highlight mw-highlight-lang-javascript mw-content-ltr" dir="ltr"><pre>var apples = 4

var bananas = 3

var domElement = ...;

domElement.$content(<p>I have {apples} apples</p>);

domElement.$append(<p>I have {apples + bananas} fruits</p>);

</pre></div>

Where <div class="mw-highlight mw-highlight-lang-javascript mw-content-ltr" dir="ltr"><pre>domElement.$content(<p>I have {apples} apples</p>);

</pre></div> gets compiled to this:

<div class="mw-highlight mw-highlight-lang-javascript mw-content-ltr" dir="ltr"><pre>domElement.html = "I have " + apples.toHtmlString() + " apples";

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Snobol">Snobol</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="SNOBOL" title="SNOBOL">SNOBOL</a></div>

<div class="mw-highlight mw-highlight-lang-snobol mw-content-ltr" dir="ltr"><pre> apples = 4 ; bananas = 3

Output = "I have " apples " apples."

Output = "I have " (apples + bananas) " fruits."

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples.

I have 7 fruits.

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="Swift">Swift</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Swift_(programming_language)" title="Swift (programming language)">Swift (programming language)</a></div>

In <a href="Swift_(programming_language)" title="Swift (programming language)">Swift</a>, a new String value can be created from a mix of constants, variables, literals, and expressions by including their values inside a string literal.<a href="#cite_note-17">[17]</a> Each item inserted into the string literal is wrapped in a pair of parentheses, prefixed by a backslash.

<div class="mw-highlight mw-highlight-lang-fsharp mw-content-ltr" dir="ltr"><pre>let apples = 4

print("I have \(apples) apples")

</pre></div>The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Tcl" title="Tcl">Tcl</a></div>

The Tool Command Language has always supported string interpolation in all quote-delimited strings.

<div class="mw-highlight mw-highlight-lang-tcl mw-content-ltr" dir="ltr"><pre>set apples 4

puts "I have $apples apples."

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples.

</pre></div>

In order to actually format – and not simply replace – the values, there is a formatting function.

<div class="mw-highlight mw-highlight-lang-tcl mw-content-ltr" dir="ltr"><pre>set apples 4

puts [format "I have %d apples." $apples]

</pre></div>

<div class="mw-heading mw-heading3"><h3 id="TypeScript">TypeScript</h3></div>

<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="TypeScript" title="TypeScript">TypeScript</a></div>

As of version 1.4, <a href="TypeScript" title="TypeScript">TypeScript</a> supports string interpolation using backticks <code>``</code>. Here is an example:

<div class="mw-highlight mw-highlight-lang-typescript mw-content-ltr" dir="ltr"><pre>var apples: number = 4;

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>I have 4 apples

</pre></div>

The <code>console.log</code> function can be used as a <code>printf</code> function. The above example can be rewritten, thusly:

console.log("I have %d apples", apples);

</pre></div>

The output remains the same.

<div class="mw-heading mw-heading3"><h3 id="Visual_Basic_.NET">Visual Basic .NET</h3></div>

As of Visual Basic 14, string interpolation is supported in Visual Basic.<a href="#cite_note-18">[18]</a>

<div class="mw-highlight mw-highlight-lang-vbnet mw-content-ltr" dir="ltr"><pre>name = "Tom"

Console.WriteLine($"Hello, {name}")

</pre></div>

The output will be:

<div class="mw-highlight mw-highlight-lang-output mw-content-ltr" dir="ltr"><pre>Hello, Tom

</pre></div>

<ul><li><a href="Concatenation" title="Concatenation">Concatenation</a></li>

<li><a href="Improper_input_validation" title="Improper input validation">Improper input validation</a></li>

<li><a href="Printf_format_string" class="mw-redirect" title="Printf format string">printf format string</a></li>

<li><a href="Quasi-quotation" title="Quasi-quotation">Quasi-quotation</a></li>

<li><a href="String_literal" title="String literal">String literal</a></li>

<li><a href="Substitution_(logic)" title="Substitution (logic)">Substitution</a></li></ul>

<div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2></div>

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</ol></div></div></div><div><div class="zim-footer">

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