MongoDB request DSL • opensavvy.ktmongo.dsl.query • FilterQuery • regex

regex¶

open fun Field<T, String?>.regex(pattern: String, caseInsensitive: Boolean = false, dotAll: Boolean = false, extended: Boolean = false, matchEachLine: Boolean = false)

Matches documents where the field corresponds to a given regex expression.

Example¶

class User(
    val name: String,
)

collection.find {
    User::name.regex("John .*")
}

Indexing¶

If possible, prefer using a "^" prefix. For example, if we know that a pattern will only be present at the start of a string, "^foo" will use indexes, whereas "foo" will not.

Avoid using .* at the start and end of a pattern. "foo" is identical to "foo.*", but the former can use indexes and the latter cannot.

External resources¶

Parameters¶

caseInsensitive: If true, the result is matched even if its case doesn't match. Note that this also disables index usage (even case-insensitive indexes) and ignores collation.
dotAll: If true, the dot character (.) can match newlines.
extended: If true, whitespace (except in character classes) is ignored, and segments starting from an unescaped pound (#) until a newline are ignored, similarly to a Python comment.

User::name.regex(
    pattern = """
        abc # This is a comment, it's not part of the pattern
        123
    """.trimIndent(),
    extended = true,
)

which is identical to the non-extended pattern "abc123".

matchEachLine: If true, the special characters ^ and $ match the beginning and end of each line, instead of matching the beginning and end of the entire string. Therefore, "^S" will match "First line\nSecond line", which would not match otherwise.

open fun KProperty1<T, String?>.regex(pattern: String, caseInsensitive: Boolean = false, dotAll: Boolean = false, extended: Boolean = false, matchEachLine: Boolean = false)