Information AboutTilde |
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The tilde (~) is a Grapheme with several uses. The name of the character comes from Spanish , from the Latin ''titulus'' meaning a title or superscription, and is pronounced "TILL-duh" ( IPA ) in English or "TEAL-dey" in Spanish. It was originally written over a letter as a mark of Abbreviation (see below), but has since acquired a number of other uses as a Diacritic mark or a character in its own right. In the latter capacity (especially in Lexicography ) it is also sometimes known as the '''swung dash''' (usually lengthened to ⁓). DIACRITICAL USE In languages, the tilde is a diacritic mark (~) placed over a Letter to indicate a change in pronunciation, such as Nasalisation . It was originally used to make Abbreviation s in Latin documents. When an ''n'' or ''m'' followed a vowel, it was often omitted, and a tilde (i.e. a small ''n'') was placed over the preceding vowel to indicate the loss of the nasal. This is the origin of the use of tilde to indicate nasalization. The practice of using the tilde over a vowel to indicate omission of an "n" or "m" continued in printed books in French as a means of reducing text length until the 17th century. The tilde was also used occasionally over other letters to indicate other abbreviations, such as over the letter "q" to signify the word "que" (fr. "that"). In Estonian , ''õ'' is a separate letter, representing a separate vowel sound. In the Polytonic Orthography of Greek , the tilde appears as a variant of the Circumflex Accent , representing a rise in Pitch followed by a return to standard pitch. In Portuguese , the tilde marks a Nasal Vowel . In Spanish and Galician tilde over ''n'' (''ñ'') is a separate letter (called '' Eñe '') and is a Palatal n ( IPA ). This phoneme is written ''nh'' in Portuguese, ''gn'' in French and Italian , ''ny'' in Catalan , Hungarian and Swahili , ''ň'' in Czech and ''ń'' in Polish . The sound is that of the "gn" in "lasagna" and the "ni" sound in "onion" and "union" in many dialects of English. The Spanish word ''tilde'' refers to any Accent Mark placed over a Vowel . For example, the acute accent in the word ''Olé'' is also called a ''tilde''. In Vietnamese , a tilde over a vowel represents a dipping (ngã) tone. In the International Phonetic Alphabet (IPA), the tilde is used ''over'' a symbol to mark Nasalization and ''through'' a symbol to mark Velarization . That is, is the French city Lyon, and is the Australian English pronunciation of "cool", with the " Dark L ". LOGIC In Logic , it represents the Negation of a Proposition : thus ~ ''p'' means "it is not the case that ''p''". ELECTRONICS It can approximate the sine wave symbol (∿, U+ 223F), which is used in Electronics to indicate Alternating Current , in place of +, −, or ⎓ for Direct Current . PUNCTUATION It is sometimes used as , the tilde is also used to separate a title and a subtitle in the same line. MATHEMATICS In mathematics, the tilde, often pronounced "twiddle," is often used to denote an Equivalence Relation between two objects. Thus ''x'' ~ ''y'' means ''x'' "is equivalent to" ''y'' (Note that this is quite different from stating that ''x'' Equals ''y''). Especially, it can be used to denote the Asymptotical Equality of two functions. For example, ''f''(''x'') ~ ''g''(''x''), means that limx→∞ ''f''(''x'')/''g''(''x'') = 1. In English it is often used to represent Approximation , for example ~10 would mean "approximately 10". Similar symbols are used in mathematics, such as in π ≈ 3.14, " π is about equal to 3.14". Since the double-tilde ( ≈ ) is not available from the Keyboard except on the Macintosh (where it is Option-x), the tilde (~) became a substitute for use in Typed entry. There is also a triple-tilde ( ≋ ), which is used to show Congruence . In Mathematical Logic , ~ is used to represent Negation . ''~p'' means "not p". See the Logic Section above. COMPUTING Directories and URLs In Unix Shell s, the tilde indicates the current user's Home Directory (e.g., /home/''username''). When prepended to a particular username, it indicates that user's home directory (e.g., ~janedoe for the home directory of user janedoe, typically /home/janedoe). When some Unix shell commands overwrite a file, they can be made to keep a backup by renaming the original file as filename~. Used in usage of the tilde. However, when accessed from the web, file access is usually directed to a Subdirectory in the user's home directory, such as /home/''username''/public_html or /home/''username''/www. In URLs, the characters %7E (or %7e) may substitute a tilde if an input device lacks a tilde key. Thus, Computer languages It is used in the Perl Programming Language as part of the pattern match operators for Regular Expression s:
The popularity of Perl's regular expression and syntax has led to the use of these operators in other programming languages, such as Ruby . In the C and C++ Programming Language s, the tilde character is used to invert the Bit s of an Integer . In C++, the tilde is also used as the first character in a Class 's Method name (where the rest of the name must be the same name as the class) to indicate a Destructor - a special method which is called at the end of the Object's Life . In the D Programming Language , the tilde is used as an Array Concatenation operator, as well as to indicate an object destructor. In the CSS stylesheet language, the tilde is used for the indirect adjacent combinator as part of a selector. In the Inform programming language, the tilde is used to indicate a quotation mark inside a quoted string. In "text mode" of the LaTeX typesetting language a stand-alone tilde can be obtained with \~{} and for use as a diacritics, e.g., like \~{n} rendering "ñ".In "math mode" a stand-alone tilde can be written as ilde{~} and as diacritics, e.g., ilde{x}. For a wider tilde the \widetilde can be used. The \sim command produce a tilde-like character that is often used in Probability mathematical Equations , and the double-tilde is obtained with \approx.In both text and math mode a tilde on its own ( ~ |