Wolfram Language and Unicode

By Xah Lee. Date: . Last updated: .

This page explains some tech detail about how Wolfram Language deals with Unicode characters.

WolframLang supports Unicode characters, such as math symbols (U+2192: RIGHTWARDS ARROW) or Greek α (U+3B1: GREEK SMALL LETTER ALPHA) or Chinese and any Unicode character.

However, WolframLang source code and the notebook, is saved in ASCII format only. [see Wolfram Language File Encoding]

Syntax of Unicode Characters

When you paste text containing Unicode characters into Wolfram notebook, any unicode character will be shown as is. But the underlying syntax or Notebook will convert it to one of:

What is Named Character

Named character is a set of characters that have the syntax \[Name]

example of WolframLang named characters
GlyphSyntax
é\[EAcute]
É\[CapitalEAcute]
α\[Alpha]
Δ\[CapitalDelta]
\[CirclePlus]
\[Because]
\[Element]
\[Equivalent]
\[DoubleStruckCapitalR]

So, when you type \[Alpha], it is displayed as α. As of 2021-06-06, there are 1009 named chars. ListingOfNamedCharacters

Some Named Chars Are Not in Unicode

Some of the named chars are not in Unicode. For example:

Wolfram Language wolf ram char Wolfram Language icon char 2021-06-06 Wolfram Language special char 2021-06-06 MzRbH
Wolfram Language only characters

Some Unicode Math Symbols Are Not in Named Chars

Many uncommon Math Symbols in Unicode [see Unicode Math Symbols ∑ ∫ π² ∞] are not WolframLang named characters. For example:

Also, Chinese chars, Arabic alphabets etc, are not Wolfram Language named chars.

Map of Unicode to Named Character

Some unicode char such as π (U+3C0: GREEK SMALL LETTER PI) maps to the named char \[Pi].

However, some unicode char such as (U+211D: DOUBLE-STRUCK CAPITAL R) does not map to the “same looking” named char \[DoubleStruckCapitalR]

Am not aware of a document that list all the named characters and the unicode they map to, if any.

Interpretation of Unicode Characters

When you paste in a unicode character, how does Wolfram Language interprete it?

If Not a Named Character

If the character does not map to one of the named character, it is treated like any letter, such as a b c. You can use it in variable name or function name. For example:

Table[♥ , {♥, 1, 5}]

(* {1, 2, 3, 4, 5} *)

Type of Named Chars: Letter/Letter-Like Forms vs Operator

A named character is one of two types:

Each character in these class may or may not have builtin meaning.

Here's a tree illustration:

Letter/Letter-Like-Form vs Operator

If it's letter or letter-like forms, either it has a builtin meaning, such as °, π, , or it is treated as any letter, such as λ. It is treated the same as any of a, b, c etc. You can use it as part of variable/function name.

If it's a operator, either it has a builtin meaning, such as Or it does not have builtin meaning, such as .

However, any operator character has builtin meaning of its syntactic structure and precedence.

Of the named chars, many has special meaning in Wolfram Language. For example, π \[Pi] is automatically considered identical to the built-in symbol Pi, which means the mathematical constant. (So, if you type \[Pi] or \:03c0, they are displayed as π with meaning of Pi.). Here's some examples of special meaning named chars.

GlyphWolfram Language's nameUnicode nameUnicode hexidecimalDefault Interpretation
π\[Pi]GREEK SMALL LETTER PI03c0Pi
\[Infinity]INFINITY221eInfinity
\[Sqrt]SQUARE ROOT221aoperator for Sqrt
\[GreaterEqual]GREATER-THAN OR EQUAL TO2265operator for GreaterEqual
\[Intersection]N-ARY INTERSECTION22c2operator for Intersection
\[Sum]N-ARY SUMMATION2211part of operator for Sum
\[Integral]INTEGRAL222bpart of operator for Integrate
\[CirclePlus]CIRCLED PLUS2295operator for CirclePlus

See:

keyboard Shortcut Alias for Named Chars

Some of the named char has one or more aliases for ease of input. For example, to enter α, you can type EscapeaEscape or EscapealphaEscape. Here's some examples:

GlyphCommon Alias
αa
πp
inf
<=
°deg
ΔD
el
->

Inputting Special Chars

You can input a special character by:

See also:

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