Camel case (sometimes stylized as camelCase or CamelCase, also known as camel caps or more formally as medial capitals) is the practice of writing phrases without spaces or punctuation. The format indicates the separation of words with a single capitalized letter, and the first word starting with either case. Common examples include ""YouTube", "iPhone" and "eBay". It is also sometimes used in online usernames such as "JohnSmith", and to make multi-word domain names more legible, for example in promoting "EasyWidgetCompany.com".
Camel Space For Mac Os
Camel case is often used as a naming convention in computer programming, but is an ambiguous definition due to the optional capitalization of the first letter. Some programming styles prefer camel case with the first letter capitalized, others not.[1][2][3] For clarity, this article calls the two alternatives upper camel case (initial uppercase letter, also known as Pascal case or bumpy case) and lower camel case (initial lowercase letter, also known as dromedary case). Some people and organizations, notably Microsoft, use the term camel case only for lower camel case, designating Pascal case for the upper camel case.[2]
Camel case is distinct from title case, which capitalizes all words but retains the spaces between them, and from Tall Man lettering, which uses capitals to emphasize the differences between similar-looking product names such as "predniSONE" and "predniSOLONE". Camel case is also distinct from snake case, which uses underscores interspersed with lowercase letters (sometimes with the first letter capitalized). A combination of snake and camel case (identifiers Written_Like_This) is recommended in the Ada 95 style guide.[4]
In Irish, camel case is used when an inflectional prefix is attached to a proper noun, for example i nGaillimh ("in Galway"), from Gaillimh ("Galway"); an tAlbanach ("the Scottish person"), from Albanach ("Scottish person"); and go hÉirinn ("to Ireland"), from Éire ("Ireland"). In recent Scottish Gaelic orthography, a hyphen has been inserted: an t-Albannach.
In Chinese pinyin, camel case is sometimes used for place names so that readers can more easily pick out the different parts of the name. For example, places like Beijing (北京), Qinhuangdao (秦皇岛), and Daxing'anling (大兴安岭) can be written as BeiJing, QinHuangDao, and DaXingAnLing respectively, with the number of capital letters equaling the number of Chinese characters. Writing word compounds only by the initial letter of each character is also acceptable in some cases, so Beijing can be written as BJ, Qinghuangdao as QHD, and Daxing'anling as DXAL.
Medial capitals are traditionally used in abbreviations to reflect the capitalization that the words would have when written out in full, for example in the academic titles PhD or BSc. A more recent example is NaNoWriMo, a contraction of National Novel Writing Month and the designation for both the annual event and the nonprofit organization that runs it. In German, the names of statutes are abbreviated using embedded capitals, e.g. StGB for Strafgesetzbuch (Criminal Code), PatG for Patentgesetz (Patent Act), BVerfG for Bundesverfassungsgericht (Federal Constitutional Court), or the very common GmbH, for Gesellschaft mit beschränkter Haftung (private limited company). In this context, there can even be three or more camel case capitals, e.g. in TzBfG for Teilzeit- und Befristungsgesetz (Act on Part-Time and Limited Term Occupations). In French, camel case acronyms such as OuLiPo (1960) were favored for a time as alternatives to initialisms.
The first systematic and widespread use of medial capitals for technical purposes was the notation for chemical formulas invented by the Swedish chemist Jacob Berzelius in 1813. To replace the multitude of naming and symbol conventions used by chemists until that time, he proposed to indicate each chemical element by a symbol of one or two letters, the first one being capitalized. The capitalization allowed formulas like "NaCl" to be written without spaces and still be parsed without ambiguity.[24][25]
Multiple-word descriptive identifiers with embedded spaces such as end of file or char table cannot be used in most programming languages because the spaces between the words would be parsed as delimiters between tokens. The alternative of running the words together as in endoffile or chartable is difficult to understand and possibly misleading; for example, chartable is an English word (able to be charted), whereas charTable means a table of chars .
However, this solution was not adequate for mathematically-oriented languages such as FORTRAN (1955) and ALGOL (1958), which used the hyphen as an infix subtraction operator. FORTRAN ignored blanks altogether, so programmers could use embedded spaces in variable names. However, this feature was not very useful since the early versions of the language restricted identifiers to no more than six characters.
The Smalltalk language, which was developed originally on the Alto, also uses camel case instead of underscores. This language became quite popular in the early 1980s, and thus may also have been instrumental in spreading the style outside PARC.
Upper camel case (or "Pascal case") is used in Wolfram Language in computer algebraic system Mathematica for predefined identifiers. User defined identifiers should start with a lower case letter. This avoids the conflict between predefined and user defined identifiers both today and in all future versions.
In the 1980s and 1990s, after the advent of the personal computer exposed hacker culture to the world, camel case then became fashionable for corporate trade names in non-computer fields as well. Mainstream usage was well established by 1990:
Style guidelines often distinguish between upper and lower camel case, typically specifying which variety should be used for specific kinds of entities: variables, record fields, methods, procedures, functions, subroutines, types, etc. These rules are sometimes supported by static analysis tools that check source code for adherence.
The original Hungarian notation for programming, for example, specifies that a lowercase abbreviation for the "usage type" (not data type) should prefix all variable names, with the remainder of the name in upper camel case; as such it is a form of lower camel case.
Programming identifiers often need to contain acronyms and initialisms that are already in uppercase, such as "old HTML file". By analogy with the title case rules, the natural camel case rendering would have the abbreviation all in uppercase, namely "oldHTMLFile". However, this approach is problematic when two acronyms occur together (e.g., "parse DBM XML" would become "parseDBMXML") or when the standard mandates lower camel case but the name begins with an abbreviation (e.g. "SQL server" would become "sQLServer"). For this reason, some programmers prefer to treat abbreviations as if they were words and write "oldHtmlFile", "parseDbmXml" or "sqlServer".[34] However, this can make it harder to recognize that a given word is intended as an acronym.[35]
Camel case is used in some wiki markup languages for terms that should be automatically linked to other wiki pages. This convention was originally used in Ward Cunningham's original wiki software, WikiWikiWeb,[36] and can be activated in most other wikis. Some wiki engines such as TiddlyWiki, Trac and PmWiki make use of it in the default settings, but usually also provide a configuration mechanism or plugin to disable it. Wikipedia formerly used camel case linking as well, but switched to explicit link markup using square brackets[37] and many other wiki sites have done the same. MediaWiki, for example, does not support camel case for linking. Some wikis that do not use camel case linking may still use the camel case as a naming convention, such as AboutUs.
Most popular command-line interfaces and scripting languages cannot easily handle file names that contain embedded spaces (usually requiring the name to be put in quotes). Therefore, users of those systems often resort to camel case (or underscores, hyphens and other "safe" characters) for compound file names like MyJobResume.pdf.
Microblogging and social networking services that limit the number of characters in a message are potential outlets for medial capitals. Using camel case between words reduces the number of spaces, and thus the number of characters, in a given message, allowing more content to fit into the limited space. Hashtags, especially long ones, often use camel case to maintain readability (e.g. #CollegeStudentProblems is easier to read than #collegestudentproblems);[38] this practice improves accessibility as screen readers recognize CamelCase in parsing composite hashtags.[39]
A 2009 study of 135 subjects comparing snake case (underscored identifiers) to camel case found that camel case identifiers were recognized with higher accuracy among all subjects. Subjects recognized snake case identifiers more quickly than camel case identifiers. Training in camel case sped up camel case recognition and slowed snake case recognition, although this effect involved coefficients with high p-values. The study also conducted a subjective survey and found that non-programmers either preferred underscores or had no preference, and 38% of programmers trained in camel case stated a preference for underscores. However, these preferences had no statistical correlation to accuracy or speed when controlling for other variables.[41]
A 2010 follow-up study used a similar study design with 15 subjects consisting of expert programmers trained primarily in snake case. It used a static rather than animated stimulus and found perfect accuracy in both styles except for one incorrect camel case response. Subjects recognized identifiers in snake case more quickly than camel case. The study used eye-tracking equipment and found that the difference in speed for its subjects was primarily due to the fact that average duration of fixations for camel-case was significantly higher than that of snake case for 3-part identifiers. The survey recorded a mixture of preferred identifier styles but again there was no correlation of preferred style to accuracy or speed.[42] 2ff7e9595c
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