Line Chart

python

import random
from typing import Any
import reflex as rx

A line chart is a type of chart used to show information that changes over time. Line charts are created by plotting a series of several points and connecting them with a straight line.

Simple Example

For a line chart we must define an rx.recharts.line() component for each set of values we wish to plot. Each rx.recharts.line() component has a data_key which clearly states which variable in our data we are tracking. In this simple example we plot pv and uv as separate lines against the name column which we set as the data_key in rx.recharts.x_axis.

python

data = [
    {"name": "Page A", "uv": 4000, "pv": 2400, "amt": 2400},
    {"name": "Page B", "uv": 3000, "pv": 1398, "amt": 2210},
    {"name": "Page C", "uv": 2000, "pv": 9800, "amt": 2290},
    {"name": "Page D", "uv": 2780, "pv": 3908, "amt": 2000},
    {"name": "Page E", "uv": 1890, "pv": 4800, "amt": 2181},
    {"name": "Page F", "uv": 2390, "pv": 3800, "amt": 2500},
    {"name": "Page G", "uv": 3490, "pv": 4300, "amt": 2100},
]


def line_simple():
    return rx.recharts.line_chart(
        rx.recharts.line(
            data_key="pv",
        ),
        rx.recharts.line(
            data_key="uv",
        ),
        rx.recharts.x_axis(data_key="name"),
        rx.recharts.y_axis(),
        data=data,
        width="100%",
        height=300,
    )

Example with Props

Our second example uses exactly the same data as our first example, except now we add some extra features to our line graphs. We add a type_ prop to rx.recharts.line to style the lines differently. In addition, we add an rx.recharts.cartesian_grid to get a grid in the background, an rx.recharts.legend to give us a legend for our graphs and an rx.recharts.graphing_tooltip to add a box with text that appears when you pause the mouse pointer on an element in the graph.

python

data = [
    {"name": "Page A", "uv": 4000, "pv": 2400, "amt": 2400},
    {"name": "Page B", "uv": 3000, "pv": 1398, "amt": 2210},
    {"name": "Page C", "uv": 2000, "pv": 9800, "amt": 2290},
    {"name": "Page D", "uv": 2780, "pv": 3908, "amt": 2000},
    {"name": "Page E", "uv": 1890, "pv": 4800, "amt": 2181},
    {"name": "Page F", "uv": 2390, "pv": 3800, "amt": 2500},
    {"name": "Page G", "uv": 3490, "pv": 4300, "amt": 2100},
]


def line_features():
    return rx.recharts.line_chart(
        rx.recharts.line(
            data_key="pv",
            type_="monotone",
            stroke="#8884d8",
        ),
        rx.recharts.line(
            data_key="uv",
            type_="monotone",
            stroke="#82ca9d",
        ),
        rx.recharts.x_axis(data_key="name"),
        rx.recharts.y_axis(),
        rx.recharts.cartesian_grid(stroke_dasharray="3 3"),
        rx.recharts.graphing_tooltip(),
        rx.recharts.legend(),
        data=data,
        width="100%",
        height=300,
    )

Layout

The layout prop allows you to set the orientation of the graph to be vertical or horizontal. The margin prop defines the spacing around the graph,

# Include margins around your graph to ensure proper spacing and enhance readability. By default, provide margins on all sides of the chart to create a visually appealing and functional representation of your data.

python

data = [
    {"name": "Page A", "uv": 4000, "pv": 2400, "amt": 2400},
    {"name": "Page B", "uv": 3000, "pv": 1398, "amt": 2210},
    {"name": "Page C", "uv": 2000, "pv": 9800, "amt": 2290},
    {"name": "Page D", "uv": 2780, "pv": 3908, "amt": 2000},
    {"name": "Page E", "uv": 1890, "pv": 4800, "amt": 2181},
    {"name": "Page F", "uv": 2390, "pv": 3800, "amt": 2500},
    {"name": "Page G", "uv": 3490, "pv": 4300, "amt": 2100},
]


def line_vertical():
    return rx.recharts.line_chart(
        rx.recharts.line(
            data_key="pv",
            stroke=rx.color("accent", 9),
        ),
        rx.recharts.line(
            data_key="uv",
            stroke=rx.color("green", 9),
        ),
        rx.recharts.x_axis(type_="number"),
        rx.recharts.y_axis(data_key="name", type_="category"),
        layout="vertical",
        margin={"top": 20, "right": 20, "left": 20, "bottom": 20},
        data=data,
        height=300,
        width="100%",
    )

Dynamic Data

Chart data can be modified by tying the data prop to a State var. Most other props, such as type_, can be controlled dynamically as well. In the following example the "Munge Data" button can be used to randomly modify the data, and the two select elements change the line type_. Since the data and style is saved in the per-browser-tab State, the changes will not be visible to other visitors.

python

initial_data = data


class LineChartState(rx.State):
    data: list[dict[str, Any]] = initial_data
    pv_type: str = "monotone"
    uv_type: str = "monotone"

    @rx.event
    def set_pv_type(self, pv_type: str):
        self.pv_type = pv_type

    @rx.event
    def set_uv_type(self, uv_type: str):
        self.uv_type = uv_type

    @rx.event
    def munge_data(self):
        for row in self.data:
            row["uv"] += random.randint(-500, 500)
            row["pv"] += random.randint(-1000, 1000)


def line_dynamic():
    return rx.vstack(
        rx.recharts.line_chart(
            rx.recharts.line(
                data_key="pv",
                type_=LineChartState.pv_type,
                stroke="#8884d8",
            ),
            rx.recharts.line(
                data_key="uv",
                type_=LineChartState.uv_type,
                stroke="#82ca9d",
            ),
            rx.recharts.x_axis(data_key="name"),
            rx.recharts.y_axis(),
            data=LineChartState.data,
            margin={"top": 20, "right": 20, "left": 20, "bottom": 20},
            width="100%",
            height=300,
        ),
        rx.hstack(
            rx.button("Munge Data", on_click=LineChartState.munge_data),
            rx.select(
                ["monotone", "linear", "step", "stepBefore", "stepAfter"],
                value=LineChartState.pv_type,
                on_change=LineChartState.set_pv_type,
            ),
            rx.select(
                ["monotone", "linear", "step", "stepBefore", "stepAfter"],
                value=LineChartState.uv_type,
                on_change=LineChartState.set_uv_type,
            ),
        ),
        width="100%",
    )

To learn how to use the sync_id, x_axis_id and y_axis_id props check out the of the area chart documentation, where these props are all described with examples.