data-validation="custom"
                                                 data-validation-regexp="(\+|\-)?\d+(\.\d+)?((e|E)(\+|\-)?\d+)?"
                                                 data-validation-help="number (Float)"/>
                                    </div>
                                </div>

     * Adds an include filter for URLs.
     * Only URLs matching this regular expression will be crawled.
     * @param regexp The regular expression for the include filter.
     */
    public void addIncludeFilter(final String regexp) {
        if (StringUtil.isNotBlank(regexp)) {
            urlFilter.addInclude(regexp);
        }
    }

    /**
     * Adds an exclude filter for URLs.

        return appendFileterPath(buf, escape(s));
    }

    /**
     * Escapes special regex characters in a string to create a literal pattern.
     * Handles anchor characters (^ and $) specially to preserve their regex meaning.
     *
     * @param s the string to escape
     * @return an escaped regex pattern, or empty string for comments
     */
    protected String escape(final String s) {

// It might be at the beginning but it might be in the middle of the printed instruction.
var fileLineRE = regexp.MustCompile(`(?:^|\()(testdata[/\\][\da-z]+\.s:\d+)(?:$|\)|:)`)

// Same as in test/run.go
var (
	errRE       = regexp.MustCompile(`// ERROR ?(.*)`)
	errQuotesRE = regexp.MustCompile(`"([^"]*)"`)
)

func testErrors(t *testing.T, goarch, file string, flags ...string) {

constraints.NotNull.message = {item} आवश्यक है।
constraints.Null.message = {item} शून्य होना चाहिए।
constraints.Past.message = {item} अतीत का मान होना चाहिए।
constraints.Pattern.message = {item} "{regexp}" से मेल नहीं खाता।
constraints.Size.message = {item} का आकार {min} और {max} के बीच होना चाहिए।
# ----------------------------------------------------------
# Hibernate Validator
# -------------------

constraints.NotNull.message = {item} wajib diisi.
constraints.Null.message = {item} harus null.
constraints.Past.message = {item} harus berupa nilai masa lalu.
constraints.Pattern.message = {item} tidak cocok dengan "{regexp}".
constraints.Size.message = Ukuran {item} harus antara {min} dan {max}.
# ----------------------------------------------------------
# Hibernate Validator
# -------------------

constraints.NotNull.message = {item} gereklidir.
constraints.Null.message = {item} boş olmalıdır.
constraints.Past.message = {item} geçmiş bir değer olmalıdır.
constraints.Pattern.message = {item}, "{regexp}" ile eşleşmiyor.
constraints.Size.message = {item} boyutu {min} ile {max} arasında olmalıdır.
# ----------------------------------------------------------
# Hibernate Validator
# -------------------

            return ".*" + Pattern.quote(p.substring(GsaConfigParser.CONTAINS.length())) + ".*";
        }

        if (p.startsWith(GsaConfigParser.REGEXP)) {
            return p.substring(GsaConfigParser.REGEXP.length());
        }

        if (p.startsWith(GsaConfigParser.REGEXP_CASE)) {
            return p.substring(GsaConfigParser.REGEXP_CASE.length());
        }

{* ../../docs_src/query_params_str_validations/tutorial003_an_py310.py hl[10] *}

## Add regular expressions { #add-regular-expressions }

You can define a <abbr title="A regular expression, regex or regexp is a sequence of characters that define a search pattern for strings.">regular expression</abbr> `pattern` that the parameter should match:

{* ../../docs_src/query_params_str_validations/tutorial004_an_py310.py hl[11] *}

Теперь вы знаете, что когда они понадобятся, вы сможете использовать их в **FastAPI**.

### `regex` из Pydantic v1 вместо `pattern` { #pydantic-v1-regex-instead-of-pattern }

До Pydantic версии 2 и до FastAPI 0.100.0 этот параметр назывался `regex`, а не `pattern`, но сейчас он устарел.

Вы всё ещё можете встретить такой код:

//// tab | Pydantic v1