# Path Parameters { #path-parameters }

You can declare path "parameters" or "variables" with the same syntax used by Python format strings:

{* ../../docs_src/path_params/tutorial001.py hl[6:7] *}

The value of the path parameter `item_id` will be passed to your function as the argument `item_id`.

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[13,18] *}

Although you use `Depends` in the parameters of your function the same way you use `Body`, `Query`, etc, `Depends` works a bit differently.

You only give `Depends` a single parameter.

This parameter must be something like a function.

   * parameters.
   */
  public MediaType withoutParameters() {
    return parameters.isEmpty() ? this : create(type, subtype);
  }

  /**
   * Replaces all parameters with the given parameters.
   *
   * @throws IllegalArgumentException if any parameter or value is invalid
   */

   * the dummy value of a constructor or method parameter is unknown.
   */
  @VisibleForTesting
  static final class ParameterNotInstantiableException extends Exception {
    public ParameterNotInstantiableException(Parameter parameter) {
      super(
          "Cannot determine value for parameter "
              + parameter
              + " of "
              + parameter.getDeclaringInvokable());
    }
  }

That configuration would change the syntax highlighting color theme:

<img src="/img/tutorial/extending-openapi/image04.png">

## Change Default Swagger UI Parameters { #change-default-swagger-ui-parameters }

FastAPI includes some default configuration parameters appropriate for most of the use cases.

It includes these default configurations:

{* ../../fastapi/openapi/docs.py ln[8:23] hl[17:23] *}

        // Verify constructor exists with expected parameters
        try {
            FessActionValidator.class.getConstructor(RequestManager.class, UserMessagesCreator.class, Class[].class);
            assertTrue("Constructor with required parameters exists", true);
        } catch (final NoSuchMethodException e) {
            fail("Constructor with RequestManager, UserMessagesCreator, and Class[] parameters should exist");
        }
    }

        } ?: return // Expected a value.

      val replaced = parameters.put(peek, parameterValue)
      peek = null
      if (replaced != null) return // Unexpected duplicate parameter.
      if (!skipCommasAndWhitespace() && !exhausted()) return // Expected ',' or EOF.
    }
    result.add(Challenge(schemeName, parameters))
  }
}

/** Returns true if any commas were skipped. */

import java.util.Map;

/**
 * Interface for script engines that can evaluate templates with parameters.
 * This interface provides a contract for different script engine implementations
 * to process template strings with parameter substitution.
 */
public interface ScriptEngine {

    /**
     * Evaluates a template string with the provided parameter map.
     * The template is processed using the script engine's templating mechanism,

        }
    }

    /**
     * Retrieves an initialization parameter, converting it to the specified class type.
     * @param <T> The type of the parameter.
     * @param key The key of the parameter.
     * @param defaultValue The default value if the parameter is not found.
     * @param clazz The class type to convert the parameter to.
     * @return The parameter value, or the default value if not found.
     */

    /**
     * Constructs a new HostIntervalController with default parameters.
     */
    public HostIntervalController() {
    }

    /**
     * Constructs a new HostIntervalController with the specified parameters.
     *
     * @param params the parameters to configure the interval controller
     */
    public HostIntervalController(final Map<String, Long> params) {