Monday, October 21, 2019
Use Is_String to Check if a Variable Is a String in PHP
Use Is_String to Check if a Variable Is a String in PHP The is_string() PHP function is used to check if a type of variable is aà string. A string is a data type, such as floating point or integer, but it represents text rather than numbers. A string uses a set of characters that includes spaces and numbers. For instance, an address such as 1234 Broadway and the sentence I ate 3 hotdogs contain numbers that should be treated as text, not as numbers. How to Use the Function Is_string is used within an if () statement to treat strings in one way and non-strings in another. It returns true or false. For example: ?php if (is_string(23)) {echo Yes;} else {echo No;}? The code above should output No because 23 is not a string. Lets try this again: ?php if (is_string(Hello World)) {echo Yes;} else {echo No;}? Since Hello World is a string, this would echo Yes. Specifying a String A string can be specified in four ways: Single quotedDouble quotedà Heredoc syntaxNowdoc Syntax Each of these methods requires strict adherenceà to PHP rules, which are available at the PHP website. The simplest method, single-quoted strings, requires special treatment when literal single quotation marks or literal backslashes appear in the string. Include a backslash in front of the single quotation mark or backslash within the string. The example below illustrates this treatment: ?php//à Outputs:à Arnold said:à Illà beà backechoà Arnold said:à I\llà beà back;//à Outputs:à Ià deletedà C:\*.*?echoà Ià deletedà C:\\*.*?;? Similar Functions is_float() ââ¬â determines if the type of variable is floatis_int() ââ¬â determines if the type of variable is integeris_bool() ââ¬â determines if a variable is a booleanis_object() ââ¬â determines if a variable is an objectis_array() ââ¬â determines if a variable is an array
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