Английская Википедия:Greater-than sign
Шаблон:Short description Шаблон:Redirect Шаблон:For Шаблон:Infobox symbol The greater-than sign is a mathematical symbol that denotes an inequality between two values. The widely adopted form of two equal-length strokes connecting in an acute angle at the right, Шаблон:Char, has been found in documents dated as far back as 1631.[1] In mathematical writing, the greater-than sign is typically placed between two values being compared and signifies that the first number is greater than the second number. Examples of typical usage include Шаблон:Math and Шаблон:Math. The less-than sign and greater-than sign always "point" to the smaller number. Since the development of computer programming languages, the greater-than sign and the less-than sign have been repurposed for a range of uses and operations.
History
The earliest known use of the symbols Шаблон:Char and Шаблон:Char is found in Шаблон:Lang (The Analytical Arts Applied to Solving Algebraic Equations) by Thomas Harriot, published posthumously in 1631.[1] The text states "Шаблон:Lang a > b Шаблон:Lang a Шаблон:Lang b (The sign of majority a > b indicates that a is greater than b)" and "Шаблон:Lang a < b Шаблон:Lang a Шаблон:Lang b (The sign of minority a < b indicates that a is less than b)."
According to historian Art Johnson, while Harriot was surveying North America, he saw a Native American with a symbol that resembled the greater-than sign,[1] in both backwards and forwards forms.[2] Johnson says it is likely Harriot developed the two symbols from this symbol.[2]
Usage in text markup
Angle brackets
The greater-than sign is sometimes used for an approximation of the closing angle bracket, Шаблон:Char. The proper Unicode character is Шаблон:Unichar. ASCII does not have angular brackets.
HTML
In HTML (and SGML and XML), the greater-than sign is used at the end of tags. The greater-than sign may be included with Шаблон:Code, while Шаблон:Code produces the greater-than or equal to sign.
E-mail and Markdown
Шаблон:See also In some early e-mail systems, the greater-than sign was used to denote quotations.[3] The sign is also used to denote quotations in Markdown.[4]
Usage in programming
The 'greater-than sign' Шаблон:Char is encoded in ASCII as character hex 3E, decimal 62. The Unicode code point is Шаблон:Unichar, inherited from ASCII.
For use with HTML, the mnemonics Шаблон:Code or Шаблон:Code may also be used.
Programming language
BASIC and C-family languages (including Java[5] and C++) use the comparison operator Шаблон:Code to mean "greater than". In Lisp-family languages, Шаблон:Code is a function used to mean "greater than". In Coldfusion and Fortran, operator Шаблон:Code means "greater than".
Double greater-than sign
Шаблон:Distinguish The double greater-than sign, Шаблон:Char, is used for an approximation of the much-greater-than sign Шаблон:Char. ASCII does not have the much greater-than sign.
The double greater-than sign is also used for an approximation of the closing guillemet, Шаблон:Char.
In Java, C, and C++, the operator Шаблон:Code is the right-shift operator. In C++ it is also used to get input from a stream, similar to the C functions Шаблон:Code and Шаблон:Code.
In Haskell, the Шаблон:Code function is a monadic operator. It is used for sequentially composing two actions, discarding any value produced by the first. In that regard, it is like the statement sequencing operator in imperative languages, such as the semicolon in C.
In XPath the Шаблон:Code operator returns true if the left operand follows the right operand in document order; otherwise it returns false.[6]
Triple greater-than sign
The triple greater-than sign, Шаблон:Char, is the unsigned-right-shift operator in JavaScript. Three greater-than signs form the distinctive prompt of the firmware console in MicroVAX, VAXstation, and DEC Alpha computers (known as the SRM console in the latter). This is also the default prompt of the Python interactive shell, often seen for code examples that can be executed interactively in the interpreter:
python
Python 3.9.2 (default, Feb 20 2021, 18:40:11)
[GCC 10.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello World")
Hello World
>>>
Greater-than sign with equals sign
The greater-than sign plus the equals sign, Шаблон:Code, is sometimes used for an approximation of the greater than or equal to sign, Шаблон:Char which was not included in the ASCII repertoire. The sign is, however, provided in Unicode, as Шаблон:Unichar.
In BASIC, Lisp-family languages, and C-family languages (including Java and C++), operator Шаблон:Code means "greater than or equal to". In Sinclair BASIC it is encoded as a single-byte code point token.
In Fortran, operator Шаблон:Code means "greater than or equal to".
In Bourne shell and Windows PowerShell, the operator Шаблон:Code means "greater than or equal to".
In Lua, operator Шаблон:Codemeans "greater than or equal to" and is used like this
x = math.random(1,9)
y = 5
if x >= y then
print("x("..x..") is more or equal to y("..y..")")
else
print("x("..x..") is less than y("..y..")")
end
expected output: Шаблон:Samp or Шаблон:Samp
Hyphen-minus with greater-than sign
In some programming languages (for example F#), the greater-than sign is used in conjunction with a hyphen-minus to create an arrow (Шаблон:Code). Arrows like these could also be used in text where other arrow symbols are unavailable. In the R programming language, this can be used as the right assignment operator. In the C, C++, and C# programming languages, this is used as a member access operator. In Swift and Python, it is used to indicate the return value type when defining a function (i.e., Шаблон:Code).
Shell scripts
In Bourne shell (and many other shells), greater-than sign is used to redirect output to a file. Greater-than plus ampersand (Шаблон:Code) is used to redirect to a file descriptor.
Spaceship operator
Greater-than sign is used in the 'spaceship operator', Шаблон:Code.
ECMAScript and C#
In ECMAScript and C#, the greater-than sign is used in lambda function expressions.
In ECMAScript:
const square = x => x * x;
console.log(square(5)); // 25
In C#:
Func<int, int> square = x => x * x;
Console.WriteLine(square(5)); // 25
PHP
In PHP, the greater-than sign is used in conjunction with the less-than sign as a not equal to operator. It is the same as the != operator.
$x = 5;
$y = 3;
$z = 5;
echo $x <> $y; // true
echo $x <> $z; // false
Unicode
Unicode provides various greater than symbols:[7]
| Symbol | Code Point | Name |
|---|---|---|
| ⍩ | U+2369 | Apl Functional Symbol Greater-Than Diaeresis |
| ⍄ | U+2344 | Apl Functional Symbol Quad Greater-Than |
| ⧁ | U+29C1 | Circled Greater-Than |
| ⦕ | U+2995 | Double Left Arc Greater-Than Bracket |
| ⪚ | U+2A9A | Double-Line Equal To Or Greater-Than |
| ⪜ | U+2A9C | Double-Line Slanted Equal To Or Greater-Than |
| ⫺ | U+2AFA | Double-Line Slanted Greater-Than Or Equal To |
| ⪢ | U+2AA2 | Double Nested Greater-Than |
| ⋝ | U+22DD | Equal To Or Greater-Than |
| ⥸ | U+2978 | Greater-Than Above Rightwards Arrow |
| ⪎ | U+2A8E | Greater-Than Above Similar Or Equal |
| ⪊ | U+2A8A | Greater-Than And Not Approximate |
| ⪈ | U+2A88 | Greater-Than And Single-Line Not Equal To |
| ≩ | U+2269 | Greater-Than But Not Equal To |
| ⋧ | U+22E7 | Greater-Than But Not Equivalent To |
| ⪧ | U+2AA7 | Greater-Than Closed By Curve |
| ⪩ | U+2AA9 | Greater-Than Closed By Curve Above Slanted Equal |
| ⪆ | U+2A86 | Greater-Than Or Approximate |
| ≥ | U+2265 | Greater-Than Or Equal To |
| ≳ | U+2273 | Greater-Than Or Equivalent To |
| ⩾ | U+2A7E | Greater-Than Or Slanted Equal To |
| ⪂ | U+2A82 | Greater-Than Or Slanted Equal To With Dot Above |
| ⪄ | U+2A84 | Greater-Than Or Slanted Equal To With Dot Above Left |
| ⪀ | U+2A80 | Greater-Than Or Slanted Equal To With Dot Inside |
| ≧ | U+2267 | Greater-Than Over Equal To |
| > | U+003E | Greater-Than Sign |
| ⩺ | U+2A7A | Greater-Than With Circle Inside |
| ⋗ | U+22D7 | Greater-Than With Dot |
| ⩼ | U+2A7C | Greater-Than With Question Mark Above |
| ≫ | U+226B | Much Greater-Than |
| ≱ | U+2271 | Neither Greater-Than Nor Equal To |
| ≵ | U+2275 | Neither Greater-Than Nor Equivalent To |
| ≯ | U+226F | Not Greater-Than |
| ⦔ | U+2994 | Right Arc Greater-Than Bracket |
| ⪠ | U+2AA0 | Similar Above Greater-Than Above Equals Sign |
| ⪞ | U+2A9E | Similar Or Greater-Than |
| ⪖ | U+2A96 | Slanted Equal To Or Greater-Than |
| ⪘ | U+2A98 | Slanted Equal To Or Greater-Than With Dot Inside |
| ⫸ | U+2AF8 | Triple Nested Greater-Than |
| ⋙ | U+22D9 | Very Much Greater-Than |
See also
- Inequality (mathematics)
- Less-than sign
- Relational operator
- Mathematical operators and symbols in Unicode
- Guillemet
- Material conditional
References
- ↑ 1,0 1,1 1,2 Шаблон:Cite journal
- ↑ 2,0 2,1 Johnson, Art. "History of Mathematical Symbols". Classic Math: History Topics for the Classroom. Dale Seymour Publications, 1994.
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite web
