Date field

Date fields allow users to input a date using a text field.

Example

from deephaven import ui

my_date_field_basic = ui.date_field(label="Date field")

Date Field Basic Example

Date types

A date field can be used to input a date.

The date field accepts the following date types as inputs:

None
LocalDate
ZoneDateTime
Instant
int
str
datetime.datetime
numpy.datetime64
pandas.Timestamp

The input will be converted to one of three Java date types:

LocalDate: in the ISO-8601 system, a LocalDate is a date without a time zone, such as “2007-12-03” or “2057-01-28”. This will create a date field with a granularity of days.
Instant: An Instant represents an unambiguous specific point on the timeline, such as 2021-04-12T14:13:07 UTC. This will create a date field with a granularity of seconds in UTC. The time zone will be rendered as the time zone in user settings.
ZonedDateTime: A ZonedDateTime represents an unambiguous specific point on the timeline with an associated time zone, such as 2021-04-12T14:13:07 America/New_York. This will create a date field with a granularity of seconds in the specified time zone. The time zone will be rendered as the specified time zone.

The start and end inputs are converted according to the following rules:

If the input is one of the three Java date types, use that type.
A date string such as “2007-12-03” will parse to a LocalDate.
A string with a date, time, and time zone such as “2021-04-12T14:13:07 America/New_York” will parse to a ZonedDateTime
All other types will attempt to convert in this order: Instant, ZonedDateTime, LocalDate

The format of the date field and the type of the value passed to the on_change handler are determined by the type of the following props in order of precedence:

value
default_value
placeholder_value

If none of these are provided, the on_change handler will be passed a field of Instant.

from deephaven import ui
from deephaven.time import to_j_local_date, dh_today, to_j_instant, to_j_zdt

zoned_date_time = to_j_zdt("1995-03-22T11:11:11.23142 America/New_York")
instant = to_j_instant("2022-01-01T00:00:00 ET")
local_date = to_j_local_date(dh_today())


@ui.component
def date_field_test(value):
    date, set_date = ui.use_state(value)
    return [ui.date_field(on_change=set_date, value=date), ui.text(str(date))]


zoned_date_field = date_field_test(zoned_date_time)
instant_date_field = date_field_test(instant)
local_date_field = date_field_test(local_date)

Value

A date field displays a placeholder by default. An initial, uncontrolled value can be provided to the date field using the defaultValue prop. Alternatively, a controlled value can be provided using the value prop.

from deephaven import ui


@ui.component
def example():
    value, set_value = ui.use_state("2020-02-03")
    return ui.flex(
        ui.date_field(
            label="Date field (uncontrolled)",
            default_value="2020-02-03",
        ),
        ui.date_field(
            label="Date field (controlled)", value=value, on_change=set_value
        ),
        gap="size-150",
        wrap=True,
    )


my_example = example()

Time zones

Date field is time zone aware when ZonedDateTime or Instant objects are provided as the value. In this case, the time zone abbreviation is displayed, and time zone concerns such as daylight saving time are taken into account when the value is manipulated.

In most cases, your data will come from and be sent to a server as an ISO 8601 formatted string.

For ZonedDateTime objects, the date field will display the specified time zone.

For Instant objects, the date field will display the time zone from the user settings.

from deephaven import ui
from deephaven.time import to_j_instant

my_zoned_date_time = ui.date_field(
    label="Date field",
    default_value="2022-11-07T00:45 America/Los_Angeles",
)

my_instant = ui.date_field(
    label="Date field",
    default_value=to_j_instant("2022-11-07T00:45Z"),
)

Granularity

The granularity prop allows you to control the smallest unit that is displayed by a date field . By default, LocalDate values are displayed with “DAY” granularity (year, month, and day), and ZonedDateTime and Instant values are displayed with “SECOND” granularity.

In addition, when a value with a time is provided but you wish to display only the date, you can set the granularity to “DAY”. This has no effect on the actual value (it still has a time component), only on what fields are displayed. In the following example, two date fields are synchronized with the same value but display different granularities.

from deephaven import ui


@ui.component
def granularity_example():
    value, set_value = ui.use_state("2021-04-07T18:45:22 UTC")
    return ui.flex(
        ui.date_field(
            label="Date field and time field",
            granularity="SECOND",
            value=value,
            on_change=set_value,
        ),
        ui.date_field(
            label="Date field", granularity="DAY", value=value, on_change=set_value
        ),
        gap="size-150",
        wrap=True,
    )


my_granularity_example = granularity_example()

HTML forms

Date field supports the name prop for integration with HTML forms. The values will be submitted to the server as ISO 8601 formatted strings according to the granularity of the value. For example, if the date field allows selecting only dates, then strings such as “2023-02-03” will be submitted, and if it allows selecting times, then strings such as “2023-02-03T08:45:00”.

from deephaven import ui

my_date_field_forms = ui.form(
    ui.date_field(label="Birth date", name="birthday"),
    ui.button("Submit", type="submit"),
    on_submit=print,
)

Labeling

A visual label should be provided for the date field using the label prop. If the date field is required, the is_required and necessity_indicator props can be used to show a required state.

from deephaven import ui

my_date_field_labeling = ui.flex(
    ui.date_field(label="Date field"),
    ui.date_field(label="Date field", is_required=True, necessity_indicator="icon"),
    ui.date_field(label="Date field", is_required=True, necessity_indicator="label"),
    ui.date_field(label="Date field", necessity_indicator="label"),
)

Events

Date fields support selection through mouse, keyboard, and touch inputs via the on_change prop, which receives the value as an argument.

from deephaven import ui


@ui.component
def event_example():
    value, set_value = ui.use_state("2020-02-03")
    return ui.date_field(
        label="Date field (controlled)", value=value, on_change=set_value
    )


my_event_example = event_example()

Validation

The is_required prop ensures that the user selects a date field. The related validation_behaviour prop allows the user to specify aria or native verification.

When the prop is set to “native”, the validation errors block form submission and are displayed as help text automatically.

from deephaven import ui


@ui.component
def date_field_validation_behaviour_example():
    return ui.form(
        ui.date_field(
            validation_behavior="native",
            is_required=True,
        )
    )


my_date_field_validation_behaviour_example = date_field_validation_behaviour_example()

Minimum and maximum values

The min_value and max_value props can also be used to ensure the value is within a specific field. Date field also validates that the end date is after the start date.

from deephaven import ui

my_date_field_basic = ui.date_field(
    label="Date field",
    min_value="2024-01-01",
    default_value="2022-02-03",
)

Label position

By default, the position of a date field’s label is above the date field , but it can be moved to the side using the label_position prop.

from deephaven import ui


@ui.component
def date_field_label_position_examples():
    return [
        ui.date_field(
            label="Test Label",
        ),
        ui.date_field(
            label="Test Label",
            label_position="side",
        ),
    ]


my_date_field_label_position_examples = date_field_label_position_examples()

Quiet state

The is_quiet prop makes a date field “quiet”. This can be useful when its corresponding styling should not distract users from surrounding content.

from deephaven import ui


my_date_field_is_quiet_example = ui.date_field(
    is_quiet=True,
)

Disabled state

The is_disabled prop disables the date field to prevent user interaction. This is useful when the date field should be visible but not available for selection.

from deephaven import ui


my_date_field_is_disabled_example = ui.date_field(
    is_disabled=True,
)

Read only

The is_read_only prop makes the date field’s value immutable. Unlike is_disabled, the date field remains focusable.

from deephaven import ui


my_date_field_is_read_only_example = ui.date_field(
    is_read_only=True,
)

Help text

A date field can have both a description and an error_message. Use the error message to offer specific guidance on how to correct the input.

The validation_state prop can be used to set whether the current date field state is valid or invalid.

from deephaven import ui


@ui.component
def date_field_help_text_examples():
    return [
        ui.date_field(
            label="Sample Label",
            description="Enter a date field.",
        ),
        ui.date_field(
            label="Sample Label",
            validation_state="valid",
            error_message="Sample invalid error message.",
        ),
        ui.date_field(
            label="Sample Label",
            validation_state="invalid",
            error_message="Sample invalid error message.",
        ),
    ]


my_date_field_help_text_examples = date_field_help_text_examples()

Contextual help

Using the contextual_help prop, a ui.contextual_help can be placed next to the label to provide additional information about the date field.

from deephaven import ui


date_field_contextual_help_example = ui.date_field(
    label="Sample Label",
    contextual_help=ui.contextual_help(ui.heading("Content tips")),
)

Custom width

The width prop adjusts the width of a date field, and the max_width prop enforces a maximum width.

from deephaven import ui


@ui.component
def date_field_width_examples():
    return [
        ui.date_field(
            width="size-3600",
        ),
        ui.date_field(
            width="size-3600",
            max_width="100%",
        ),
    ]


my_date_field_width_examples = date_field_width_examples()

Hide time zone

The time zone can be hidden using the hide_time_zone option.

from deephaven import ui

my_hide_time_zone_example = ui.date_field(
    label="Date field",
    default_value="2022-11-07T00:45 America/Los_Angeles",
    hide_time_zone=True,
)

Hour cycle

By default, date field displays times in either a 12 or 24 hour format depending on the user’s locale. However, this can be overridden using the hour_cycle prop.

from deephaven import ui


date_field_hour_cycle_example = ui.date_field(label="Date field", hour_cycle=24)

Time table filtering

Date fields can be used to filter tables with time columns.

from deephaven.time import dh_now
from deephaven import time_table, ui


@ui.component
def date_table_filter(table, start_date, end_date, time_col="Timestamp"):
    after_date, set_after_date = ui.use_state(start_date)
    before_date, set_before_date = ui.use_state(end_date)
    return [
        ui.date_field(label="Start Date", value=after_date, on_change=set_after_date),
        ui.date_field(label="End Date", value=before_date, on_change=set_before_date),
        table.where(f"{time_col} >= after_date  && {time_col} < before_date"),
    ]


SECONDS_IN_DAY = 86400
today = dh_now()
_table = time_table("PT1s").update_view(
    ["Timestamp=today.plusSeconds(SECONDS_IN_DAY*i)", "Row=i"]
)
date_filter = date_table_filter(_table, today, today.plusSeconds(SECONDS_IN_DAY * 10))

API Reference

A date field allows the user to select a date.

Returns: Element The date field element.

Parameters	Type	Default	Description
placeholder_value	DType \| None \| str \| date \| datetime \| datetime64 \| Timestamp \| int		A placeholder date that influences the format of the placeholder shown when no value is selected. Defaults to today at midnight in the user's timezone.
value	DType \| None \| str \| date \| datetime \| datetime64 \| Timestamp \| int \| UndefinedType	<deephaven.ui.types.types.UndefinedType object>	The current value (controlled).
default_value	DType \| None \| str \| date \| datetime \| datetime64 \| Timestamp \| int \| UndefinedType	<deephaven.ui.types.types.UndefinedType object>	The default value (uncontrolled).
min_value	DType \| None \| str \| date \| datetime \| datetime64 \| Timestamp \| int	None	The minimum allowed date that a user may select.
max_value	DType \| None \| str \| date \| datetime \| datetime64 \| Timestamp \| int	None	The maximum allowed date that a user may select.
granularity	Literal['DAY', 'HOUR', 'MINUTE', 'SECOND'] \| None	None	Determines the smallest unit that is displayed in the date field. By default, this is "DAY" for LocalDate, and "SECOND" otherwise.
hour_cycle	Literal[12, 24] \| None	None	Whether to display the time in 12 or 24 hour format. By default, this is determined by the user's locale.
hide_time_zone	bool	False	Whether to hide the time zone abbreviation.
should_force_leading_zeros	bool \| None	None	Whether to always show leading zeros in the month, day, and hour fields. By default, this is determined by the user's locale.
is_disabled	bool \| None	None	Whether the input is disabled.
is_read_only	bool \| None	None	Whether the input can be selected but not changed by the user.
is_required	bool \| None	None	Whether user input is required on the input before form submission.
validation_behavior	Literal['aria', 'native'] \| None	None	Whether to use native HTML form validation to prevent form submission when the value is missing or invalid, or mark the field as required or invalid via ARIA.
auto_focus	bool \| None	None	Whether the element should receive focus on render.
label	None \| bool \| int \| str \| Element \| List[NodeType]	None	The content to display as the label.
description	Element \| None	None	A description for the field. Provides a hint such as specific requirements for what to choose.
error_message	Element \| None	None	An error message for the field.
is_open	bool \| None	None	Whether the overlay is open by default (controlled).
default_open	bool \| None	None	Whether the overlay is open by default (uncontrolled).
name	str \| None	None	The name of the input element, used when submitting an HTML form.
is_quiet	bool \| None	None	Whether the date field should be displayed with a quiet style.
show_format_help_text	bool \| None	None	Whether to show the localized date format as help text below the field.
label_position	Literal['top', 'side'] \| None	None	The label's overall position relative to the element it is labeling.
label_align	Literal['start', 'end'] \| None	None	The label's horizontal alignment relative to the element it is labeling.
necessity_indicator	Literal['icon', 'label'] \| None	None	Whether the required state should be shown as an icon or text.
contextual_help	Element \| None	None	A ContextualHelp element to place next to the label.
validation_state	Literal['valid', 'invalid'] \| None	None	Whether the input should display its "valid" or "invalid" visual styling.
key	str \| None	None	A unique identifier used by React to render elements in a list.