String interpolation

DATA(apples) = 4.
WRITE |I have { apples } apples|.

The output will be:

I have 4 apples

apples=4
echo "I have $apples apples"
# or
echo "I have ${apples} apples"

The output will be:

I have 4 apples

apples = 4
print("I have $(apples) apples")
# or
print("I have {0} apples" % apples)

The output will be:

I have 4 apples

var apples = 4;
var bananas = 3;

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

[5]

The output will be:

I have 4 apples
I have 7 fruits

ColdFusion Markup Language (CFML) script syntax:

apples = 4;
writeOutput("I have #apples# apples");

Tag syntax:

<cfset apples = 4>
<cfoutput>I have #apples# apples</cfoutput>

The output will be:

I have 4 apples

apples = 4
console.log "I have #{apples} apples"

The output will be:

I have 4 apples

int apples = 4, bananas = 3;
print('I have $apples apples.');
print('I have ${apples+bananas} fruits.');

The output will be:

I have 4 apples.
I have 7 fruits.

As of 2022, Go does not have string interpolation. There have been some proposals for string interpolation in the next version of the language, Go 2.[6][7] Instead, Go uses printf format strings in the fmt.Sprintf function, string concatenation, or template libraries like text/template.

In groovy, interpolated strings are known as GStrings:[8]

def quality = "superhero"
final age = 52
def sentence = "A developer is a $quality if he is ${age <= 42 ? 'young' : 'seasoned'}"
println sentence

The output will be:

A developer is a superhero if he is seasoned

var apples = 4;
var bananas = 3;
trace('I have $apples apples.');
trace('I have ${apples+bananas} fruits.');

The output will be:[9]

I have 4 apples.
I have 7 fruits.

As of 2022, Java does not have interpolated strings, and instead uses format functions, notably the MessageFormat class (Java version 1.1 and above) and the static method String.format (Java version 5 and above). There is a proposal to add string interpolation to the Java language. This proposal aims at doing safe string interpolation, making it easier to prevent injection attacks.

JavaScript, as of the ECMAScript 2015 (ES6) standard, supports string interpolation using backticks ``. This feature is called template literals.[10] Here is an example:

const apples = 4;
const bananas = 3;
console.log(`I have ${apples} apples`);
console.log(`I have ${apples + bananas} fruits`);

The output will be:

I have 4 apples
I have 7 fruits

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

console.log(`This is the first line of text.
This is the second line of text.`);

The output will be:

This is the first line of text.
This is the second line of text.

apples = 4
bananas = 3
print("I have $apples apples and $bananas bananas, making $(apples + bananas) pieces of fruit in total.")

The output will be:

I have 4 apples and 3 bananas, making 7 pieces of fruit in total.

val quality = "superhero"
val apples = 4
val bananas = 3
val sentence = "A developer is a $quality. I have ${apples + bananas} fruits"
println(sentence)

The output will be:

A developer is a superhero. I have 7 fruits

def apples = 4;
def bananas = 3;
Console.WriteLine($"I have $apples apples.");
Console.WriteLine($"I have $(apples + bananas) fruit.");

It also supports advanced formatting features, such as:

def fruit = ["apple", "banana"];
Console.WriteLine($<#I have ..$(fruit; "\n"; f => f + "s")#>);

The output will be:

apples
bananas

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.

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" }"""

The output will be:

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

let numberOfApples = "4";
in "I have ${numberOfApples} apples"

The output will be:

I have 4 apples

const Apples := 4
const Bananas := 3
Println ("I have `(Apples) apples.\n")
Println ("I have `(Apples+Bananas) fruits.\n")

The output will be:

I have 4 apples.
I have 7 fruits.

my $apples = 4;
my $bananas = 3;
print "I have $apples apples.\n";
print "I have @{[$apples+$bananas]} fruit.\n";  # Uses the Perl array (@) interpolation.

The output will be:

I have 4 apples.
I have 7 fruit.

<?php
$apples = 5;
$bananas = 3;
echo "There are $apples apples and $bananas bananas.\n";
echo "I have {$apples} apples and {$bananas} bananas.";

The output will be:

There are 5 apples and 3 bananas.
I have 5 apples and 3 bananas.

Python supports string interpolation as of version 3.6, referred to as "formatted string literals".[11][12][13] Such a literal begins with an f or F before the opening quote, and uses braces for placeholders:

apples = 4
bananas = 3
print(f'I have {apples} apples and {bananas} bananas')

The output will be:

I have 4 apples and 3 bananas

apples = 4
puts "I have #{apples} apples"
# Format string applications for comparison:
puts "I have %s apples" % apples
puts "I have %{a} apples" % {a: apples}

The output will be:

I have 4 apples

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.[14]

Rust provides formatting via the std::fmt module, which is interfaced with through various macros such as format!, write!, and print!. These macros are converted into Rust source code at compile-time, whereby each argument interacts with a formatter. The formatter supports positional parameters, named parameters, argument types, defining various formatting traits, and capturing identifiers from the environment.

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.");

The output will be:

There are 4 apples and 3 bananas.

Scala 2.10+ provides a general facility to allow arbitrary processing of a string literal, and supports string interpolation using the included s and f string interpolators. It is also possible to write custom ones or override the standard ones.

The f 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.

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

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")

The output will be:

I have 4 apples

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

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>);

Where

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

gets compiled to this:

domElement.html = "<p>I have " + apples.toHtmlString() + " apples</p>";

   apples = 4 ; bananas = 3
   Output = "I have " apples " apples."
   Output = "I have "  (apples + bananas) " fruits."

The output will be:

I have 4 apples.
I have 7 fruits.

In Swift, a new String value can be created from a mix of constants, variables, literals, and expressions by including their values inside a string literal.[15] Each item inserted into the string literal is wrapped in a pair of parentheses, prefixed by a backslash.

let apples = 4
print("I have \(apples) apples")

The output will be:

I have 4 apples

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

set apples 4
puts "I have $apples apples."

The output will be:

I have 4 apples.

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

set apples 4
puts [format "I have %d apples." $apples]

As of version 1.4, TypeScript supports string interpolation using backticks ``. Here is an example:

var apples: number = 4;
console.log(`I have ${apples} apples`);

The output will be:

I have 4 apples

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

var apples: number = 4;
console.log("I have %d apples", apples);

The output remains the same.

As of Visual Basic 14, string interpolation is supported in Visual Basic.[16]

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

The output will be:

Hello, Tom