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< | |
---|---|

Less-than sign | |

In Unicode | U+003C < LESS-THAN SIGN (<, <) |

Different from | |

Different from | U+2329 〈 LEFT-POINTING ANGLE BRACKET |

Related | |

See also | U+003E > GREATER-THAN SIGN U+2264 ≤ LESS-THAN OR EQUAL TO U+2A7D ⩽ LESS-THAN OR SLANTED EQUAL TO used e.g. in Poland U+226A ≪ MUCH LESS-THAN |

The **less-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 left, <, has been found in documents dated as far back as the 1560s. In mathematical writing, the less-than sign is typically placed between two values being compared and signifies that the first number is less than the second number. Examples of typical usage include 1⁄2 < 1 and −2 < 0.

Since the development of computer programming languages, the less-than sign and the greater-than sign have been repurposed for a range of uses and operations.

The **less-than sign**, <, is an original ASCII character (hex 3C, decimal 60).

The less-than sign may be used for an approximation of the opening angle bracket, ⟨. ASCII does not have angle brackets but are standard in Unicode (U+2329 〈 LEFT-POINTING ANGLE BRACKET). The latter is expected in formal texts.

In BASIC, Lisp-family languages, and C-family languages (including Java and C++), comparison operator `<`

means "less than".

In Coldfusion, operator `.lt.`

means "less than".

In Fortran, operator `.LT.`

means "less than"; later versions allow `<`

.

In Bourne shell (and many other shells), operator `-lt`

means "less than". Less-than sign is used to redirect input from a file. Less-than plus ampersand (`<&`

) is used to redirect from a file descriptor.

The **double less-than sign**, <<, may be used for an approximation of the *much-less-than sign* (≪) or of the opening guillemet («). ASCII does not encode either of these signs, though they are both included in Unicode.

In Bash, Perl, and Ruby, operator `<<EOF`

(where "EOF" is an arbitrary string, but commonly "EOF" denoting "end of file") is used to denote the beginning of a here document.

In C and C++, operator `<<`

represents a binary left shift.

In the C++ Standard Library, operator `<<`

, when applied on an output stream, acts as *insertion operator* and performs an output operation on the stream.

In Ruby, operator `<<`

acts as *append operator* when used between an array and the value to be appended.

In XPath the `<<`

operator returns true if the left operand precedes the right operand in document order; otherwise it returns false.^{[1]}

In PHP, operator `<<<OUTPUT`

is used to denote the beginning of a heredoc statement (where `OUTPUT`

is an arbitrary named variable.)

In Bash, `<<<word`

is used as a "here string", where `word`

is expanded and supplied to the command on its standard input, similar to a heredoc.

The less-than sign with the equals sign, `<=`

, may be used for an approximation of the less-than-or-equal-to sign, ≤. ASCII does not have a less-than-or-equal-to sign, but Unicode defines it at code point U+2264.

In BASIC, Lisp-family languages, and C-family languages (including Java and C++), operator `<=`

means "less than or equal to". In Sinclair BASIC it is encoded as a single-byte code point token.

In Prolog, `=<`

means "less than or equal to" (as distinct from the arrow `<=`

).

In Fortran, operators `.LE.`

and `<=`

both mean "less than or equal to".

In Bourne shell and Windows PowerShell, the operator `-le`

means "less than or equal to".

In the R programming language, the less-than sign is used in conjunction with a hyphen-minus to create an arrow (`<-`

), this can be used as the left assignment operator.

Less-than sign is used in the spaceship operator.

In HTML (and SGML and XML), the less-than sign is used at the beginning of tags. The less-than sign may be included with `<`

. The less-than-or-equal-to sign, ≤, may be included with `≤`

.

Unicode provides various Less Than Symbol:^{[2]}

Symbol | Name | Code Point |
---|---|---|

⍃ | Apl Functional Symbol Quad Less Than | U+2343 |

⧀ | Circled Less Than | U+29C0 |

⦖ | Double Right Arc Less Than Bracket | U+2996 |

⋜ | Equal To Or Less Than | U+22DC |

⦓ | Left Arc Less Than Bracket | U+2993 |

⥷ | Leftwards Arrow Through Less Than | U+2977 |

⥶ | Less Than Above Leftwards Arrow | U+2976 |

≨ | Less Than But Not Equal To | U+2268 |

⋦ | Less Than But Not Equivalent To | U+22E6 |

≤ | Less Than Or Equal To | U+2264 |

≲ | Less Than Or Equivalent To | U+2272 |

≦ | Less Than Over Equal To | U+2266 |

< | Less Than Sign | U+003C |

⩹ | Less Than With Circle Inside | U+2A79 |

⋖ | Less Than With Dot | U+22D6 |

≪ | Much Less Than | U+226A |

≰ | Neither Less Than Nor Equal To | U+2270 |

≴ | Neither Less Than Nor Equivalent To | U+2274 |

≮ | Not Less Than | U+226E |

⋘ | Very Much Less Than | U+22D8 |

In an inequality, the less-than sign and greater-than sign always "point" to the smaller number. Put another way, the "jaws" (the wider section of the symbol) always direct to the larger number.