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String Aggregation Operators

String expressions, with the exception of $concat, only have a well-defined behavior for strings of ASCII characters.

$concat behavior is well-defined regardless of the characters used.

注解

For details on specific operator, including syntax and examples, click on the specific operator to go to its reference page.

Name Description
$concat Concatenates any number of strings.
$indexOfBytes Searches a string for an occurence of a substring and returns the UTF-8 byte index of the first occurence. If the substring is not found, returns -1.
$indexOfCP Searches a string for an occurence of a substring and returns the UTF-8 code point index of the first occurence. If the substring is not found, returns -1.
$split Splits a string into substrings based on a delimiter. Returns an array of substrings. If the delimiter is not found within the string, returns an array containing the original string.
$strcasecmp Performs case-insensitive string comparison and returns: 0 if two strings are equivalent, 1 if the first string is greater than the second, and -1 if the first string is less than the second.
$strLenBytes Returns the number of UTF-8 encoded bytes in a string.
$strLenCP Returns the number of UTF-8 code points in a string.
$strcasecmp Performs case-insensitive string comparison and returns: 0 if two strings are equivalent, 1 if the first string is greater than the second, and -1 if the first string is less than the second.
$substr Deprecated. Use $substrBytes or $substrCP.
$substrBytes Returns the substring of a string. Starts with the character at the specified UTF-8 byte index (zero-based) in the string and continues for the specified number of bytes.
$substrCP Returns the substring of a string. Starts with the character at the specified UTF-8 code point (CP) index (zero-based) in the string and continues for the number of code points specified.
$toLower Converts a string to lowercase. Accepts a single argument expression.
$toUpper Converts a string to uppercase. Accepts a single argument expression.