# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022-2025) # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. from __future__ import annotations from typing import TYPE_CHECKING, cast from streamlit.proto.Empty_pb2 import Empty as EmptyProto from streamlit.proto.Skeleton_pb2 import Skeleton as SkeletonProto from streamlit.runtime.metrics_util import gather_metrics if TYPE_CHECKING: from streamlit.delta_generator import DeltaGenerator class EmptyMixin: @gather_metrics("empty") def empty(self) -> DeltaGenerator: """Insert a single-element container. Inserts a container into your app that can be used to hold a single element. This allows you to, for example, remove elements at any point, or replace several elements at once (using a child multi-element container). To insert/replace/clear an element on the returned container, you can use ``with`` notation or just call methods directly on the returned object. See examples below. Examples -------- Inside a ``with st.empty():`` block, each displayed element will replace the previous one. >>> import streamlit as st >>> import time >>> >>> with st.empty(): ... for seconds in range(10): ... st.write(f"⏳ {seconds} seconds have passed") ... time.sleep(1) ... st.write(":material/check: 10 seconds over!") ... st.button("Rerun") .. output:: https://doc-empty.streamlit.app/ height: 220px You can use an ``st.empty`` to replace multiple elements in succession. Use ``st.container`` inside ``st.empty`` to display (and later replace) a group of elements. >>> import streamlit as st >>> import time >>> >>> st.button("Start over") >>> >>> placeholder = st.empty() >>> placeholder.markdown("Hello") >>> time.sleep(1) >>> >>> placeholder.progress(0, "Wait for it...") >>> time.sleep(1) >>> placeholder.progress(50, "Wait for it...") >>> time.sleep(1) >>> placeholder.progress(100, "Wait for it...") >>> time.sleep(1) >>> >>> with placeholder.container(): ... st.line_chart({"data": [1, 5, 2, 6]}) ... time.sleep(1) ... st.markdown("3...") ... time.sleep(1) ... st.markdown("2...") ... time.sleep(1) ... st.markdown("1...") ... time.sleep(1) >>> >>> placeholder.markdown("Poof!") >>> time.sleep(1) >>> >>> placeholder.empty() .. output:: https://doc-empty-placeholder.streamlit.app/ height: 600px """ empty_proto = EmptyProto() return self.dg._enqueue("empty", empty_proto) @gather_metrics("_skeleton") def _skeleton(self, *, height: int | None = None) -> DeltaGenerator: """Insert a single-element container which displays a "skeleton" placeholder. Inserts a container into your app that can be used to hold a single element. This allows you to, for example, remove elements at any point, or replace several elements at once (using a child multi-element container). To insert/replace/clear an element on the returned container, you can use ``with`` notation or just call methods directly on the returned object. See some of the examples below. This is an internal method and should not be used directly. Parameters ---------- height: int or None Desired height of the skeleton expressed in pixels. If None, a default height is used. """ skeleton_proto = SkeletonProto() if height: skeleton_proto.height = height return self.dg._enqueue("skeleton", skeleton_proto) @property def dg(self) -> DeltaGenerator: """Get our DeltaGenerator.""" return cast("DeltaGenerator", self)