String operators

Learn how to use and combine different query operators for searching string data types.

The table summarizes the string operators available in APL.

Operator	Description	Case sensitive	Example
==	Equals	Yes	"aBc" == "aBc"
!=	Not equals	Yes	"abc" != "ABC"
=~	Equals	No	"abc" =~ "ABC"
!~	Not equals	No	"aBc" !~ "xyz"
contains	RHS occurs as a subsequence of LHS	No	"parentSpanId" contains "Span"
!contains	RHS doesn’t occur in LHS	No	"parentSpanId" !contains "abc"
contains_cs	RHS occurs as a subsequence of LHS	Yes	"parentSpanId" contains_cs "Id"
!contains_cs	RHS doesn’t occur in LHS	Yes	"parentSpanId" !contains_cs "Id"
startswith	RHS is an initial subsequence of LHS	No	"parentSpanId" startswith "parent"
!startswith	RHS isn’t an initial subsequence of LHS	No	"parentSpanId" !startswith "Id"
startswith_cs	RHS is an initial subsequence of LHS	Yes	"parentSpanId" startswith_cs "parent"
!startswith_cs	RHS isn’t an initial subsequence of LHS	Yes	"parentSpanId" !startswith_cs "parent"
endswith	RHS is a closing subsequence of LHS	No	"parentSpanId" endswith "Id"
!endswith	RHS isn’t a closing subsequence of LHS	No	"parentSpanId" !endswith "Span"
endswith_cs	RHS is a closing subsequence of LHS	Yes	"parentSpanId" endswith_cs "Id"
!endswith_cs	RHS isn’t a closing subsequence of LHS	Yes	"parentSpanId" !endswith_cs "Span"
in	Equals to one of the elements	Yes	"abc" in ("123", "345", "abc")
!in	Not equals to any of the elements	Yes	"bca" !in ("123", "345", "abc")
in~	Equals to one of the elements	No	"abc" in~ ("123", "345", "ABC")
!in~	Not equals to any of the elements	No	"bca" !in~ ("123", "345", "ABC")
matches regex	LHS contains a match for RHS	Yes	"parentSpanId" matches regex "g.*r"
!matches regex	LHS doesn’t contain a match for RHS	Yes	"parentSpanId" !matches regex "g.*r"
has	RHS is a whole term in LHS	No	"North America" has "america"
!has	RHS isn’t a whole term in LHS	No	"North America" !has "america"
has_cs	RHS is a whole term in LHS	Yes	"North America" has_cs "America"
!has_cs	RHS isn’t a whole term in LHS	Yes	"North America" !has_cs "America"
hasprefix	LHS string starts with the RHS string	No	"Admin_User" hasprefix "Admin"
!hasprefix	LHS string doesn’t start with the RHS string	No	"Admin_User" !hasprefix "Admin"
hasprefix_cs	LHS string starts with the RHS string	Yes	"DOCS_file" hasprefix_cs "DOCS"
!hasprefix_cs	LHS string doesn’t start with the RHS string	Yes	"DOCS_file" !hasprefix_cs "DOCS"
hassuffix	LHS string ends with the RHS string	No	"documentation.docx" hassuffix ".docx"
!hassuffix	LHS string doesn’t end with the RHS string	No	"documentation.docx" !hassuffix ".docx"
hassuffix_cs	LHS string ends with the RHS string	Yes	"Document.HTML" hassuffix_cs ".HTML"
!hassuffix_cs	LHS string doesn’t end with the RHS string	Yes	"Document.HTML" !hassuffix_cs ".HTML"

RHS = right-hand side of the expression LHS = left-hand side of the expression

Case-sensitivity

Operators with _cs suffix are case-sensitive.

When two operators do the same task, use the case-sensitive one for better performance.

For example:

• Instead of =~, use ==
• Instead of in~, use in
• Instead of contains, use contains_cs

Best practices

• Use case-sensitive operators when you know the case to improve performance.
• Avoid complex regular expressions for basic matching tasks. Use basic string operators instead.
• When matching against a set of values, ensure the set is as small as possible to improve performance.
• For matching substrings, use prefix or suffix matching instead of general substring matching for better performance.

Equality and inequality operators

Operators:

• ==
• !=
• =~
• !~
• in
• !in
• in~
• !in~

Query examples:

"get" == "get"
"get" != "GET"
"get" =~ "GET"
"get" !~ "put"
"get" in ("get", "put", "delete")

• Use == or != for exact match comparisons when case sensitivity is important.
• Use =~ or !~ for case-insensitive comparisons or when you don’t know the exact case.
• Use in or !in for checking membership within a set of values which can be efficient for a small set of values.

Subsequence-matching operators

Operators:

• contains
• !contains
• contains_cs
• !contains_cs
• startswith
• !startswith
• startswith_cs
• !startswith_cs
• endswith
• !endswith
• endswith_cs
• !endswith_cs

Query examples:

"parentSpanId" contains "Span" // True
"parentSpanId" !contains "xyz" // True
"parentSpanId" startswith "parent" // True
"parentSpanId" endswith "Id" // True
"parentSpanId" contains_cs "Span" // True if parentSpanId is "parentSpanId", False if parentSpanId is "parentspanid" or "PARENTSPANID"
"parentSpanId" startswith_cs "parent" // True if parentSpanId is "parentSpanId", False if parentSpanId is "ParentSpanId" or "PARENTSPANID"
"parentSpanId" endswith_cs "Id" // True if parentSpanId is "parentSpanId", False if parentSpanId is "parentspanid" or "PARENTSPANID"

Use case-sensitive operators (contains_cs, startswith_cs, endswith_cs) when you know the case to improve performance.

Regular-expression-matching operators

Operators:

• matches regex
• !matches regex

Query examples:

"parentSpanId" matches regex "p.*Id" // True
"parentSpanId" !matches regex "x.*z" // True

Avoid complex regular expressions or use string operators for simple substring, prefix, or suffix matching.

Term-matching operators

Operators:

• has
• !has
• has_cs
• !has_cs
• hasprefix
• !hasprefix
• hasprefix_cs
• !hasprefix_cs
• hassuffix
• !hassuffix
• hassuffix_cs
• !hassuffix_cs

Query examples:

"North America" has "america" // True
"North America" !has "america" // False
"North America" has_cs "America" // True
"North America" !has_cs "America" // False
"Admin_User" hasprefix "Admin" // True
"Admin_User" !hasprefix "Admin" // False
"DOCS_file" hasprefix_cs "DOCS" // True
"DOCS_file" !hasprefix_cs "DOCS" // False
"documentation.docx" hassuffix ".docx" // True
"documentation.docx" !hassuffix ".docx" // False
"Document.HTML" hassuffix_cs ".HTML" // True
"Document.HTML" !hassuffix_cs ".HTML" // False

• Use has or has_cs for term matching which can be more efficient than regular expression matching for simple term searches.
• Use has_cs when you know the case to improve performance.
• Unlike the contains operator, which matches any substring, the has operator looks for exact terms, ensuring more precise results.

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