Show Sidebar Hide Sidebar

Line Charts in Python

How to make line charts in Python with Plotly. Examples on creating and styling line charts in Python with Plotly.

Line Plot with plotly.express

Plotly Express functions take as a first argument a tidy pandas.DataFrame. With px.line, each data point is represented as a vertex (which location is given by the x and y columns) of a polyline mark in 2D space.

For more examples of line plots, see the line and scatter notebook.

Simple Line Plot with plotly.express

In [1]:
import plotly.express as px

gapminder = px.data.gapminder().query("country=='Canada'")
fig = px.line(gapminder, x="year", y="lifeExp", title='Life expectancy in Canada')
fig.show()

Line Plot with column encoding color

In [2]:
import plotly.express as px

gapminder = px.data.gapminder().query("continent=='Oceania'")
fig = px.line(gapminder, x="year", y="lifeExp", color='country')
fig.show()
In [3]:
import plotly.express as px

gapminder = px.data.gapminder().query("continent != 'Asia'") # remove Asia for visibility
fig = px.line(gapminder, x="year", y="lifeExp", color="continent",
              line_group="country", hover_name="country")
fig.show()

 Line Plot with go.Scatter

When data are not available as tidy dataframes, it is possible to use the more generic go.Scatter function from plotly.graph_objects. Whereas plotly.express has two functions scatter and line, go.Scatter can be used both for plotting points (makers) or lines, depending on the value of mode. The different options of go.Scatter are documented in its reference page.

Simple Line Plot

In [4]:
import plotly.graph_objects as go
import numpy as np

x = np.arange(10)

fig = go.Figure(data=go.Scatter(x=x, y=x**2))
fig.show()

Line Plot Modes

In [5]:
import plotly.graph_objects as go

# Create random data with numpy
import numpy as np
np.random.seed(1)

N = 100
random_x = np.linspace(0, 1, N)
random_y0 = np.random.randn(N) + 5
random_y1 = np.random.randn(N)
random_y2 = np.random.randn(N) - 5

# Create traces
fig = go.Figure()
fig.add_trace(go.Scatter(x=random_x, y=random_y0,
                    mode='lines',
                    name='lines'))
fig.add_trace(go.Scatter(x=random_x, y=random_y1,
                    mode='lines+markers',
                    name='lines+markers'))
fig.add_trace(go.Scatter(x=random_x, y=random_y2,
                    mode='markers', name='markers'))

fig.show()

Style Line Plots

This example styles the color and dash of the traces, adds trace names, modifies line width, and adds plot and axes titles.

In [6]:
import plotly.graph_objects as go

# Add data
month = ['January', 'February', 'March', 'April', 'May', 'June', 'July',
         'August', 'September', 'October', 'November', 'December']
high_2000 = [32.5, 37.6, 49.9, 53.0, 69.1, 75.4, 76.5, 76.6, 70.7, 60.6, 45.1, 29.3]
low_2000 = [13.8, 22.3, 32.5, 37.2, 49.9, 56.1, 57.7, 58.3, 51.2, 42.8, 31.6, 15.9]
high_2007 = [36.5, 26.6, 43.6, 52.3, 71.5, 81.4, 80.5, 82.2, 76.0, 67.3, 46.1, 35.0]
low_2007 = [23.6, 14.0, 27.0, 36.8, 47.6, 57.7, 58.9, 61.2, 53.3, 48.5, 31.0, 23.6]
high_2014 = [28.8, 28.5, 37.0, 56.8, 69.7, 79.7, 78.5, 77.8, 74.1, 62.6, 45.3, 39.9]
low_2014 = [12.7, 14.3, 18.6, 35.5, 49.9, 58.0, 60.0, 58.6, 51.7, 45.2, 32.2, 29.1]

fig = go.Figure()
# Create and style traces
fig.add_trace(go.Scatter(x=month, y=high_2014, name='High 2014',
                         line=dict(color='firebrick', width=4)))
fig.add_trace(go.Scatter(x=month, y=low_2014, name = 'Low 2014',
                         line=dict(color='royalblue', width=4)))
fig.add_trace(go.Scatter(x=month, y=high_2007, name='High 2007',
                         line=dict(color='firebrick', width=4,
                              dash='dash') # dash options include 'dash', 'dot', and 'dashdot'
))
fig.add_trace(go.Scatter(x=month, y=low_2007, name='Low 2007',
                         line = dict(color='royalblue', width=4, dash='dash')))
fig.add_trace(go.Scatter(x=month, y=high_2000, name='High 2000',
                         line = dict(color='firebrick', width=4, dash='dot')))
fig.add_trace(go.Scatter(x=month, y=low_2000, name='Low 2000',
                         line=dict(color='royalblue', width=4, dash='dot')))

# Edit the layout
fig.update_layout(title='Average High and Low Temperatures in New York',
                   xaxis_title='Month',
                   yaxis_title='Temperature (degrees F)')


fig.show()

Connect Data Gaps

In [7]:
import plotly.graph_objects as go

x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

fig = go.Figure()

fig.add_trace(go.Scatter(
    x=x,
    y=[10, 20, None, 15, 10, 5, 15, None, 20, 10, 10, 15, 25, 20, 10],
    name = '<b>No</b> Gaps', # Style name/legend entry with html tags
    connectgaps=True # override default to connect the gaps
))
fig.add_trace(go.Scatter(
    x=x,
    y=[5, 15, None, 10, 5, 0, 10, None, 15, 5, 5, 10, 20, 15, 5],
    name='Gaps',
))

fig.show()

Interpolation with Line Plots

In [8]:
import plotly.graph_objects as go
import numpy as np

x = np.array([1, 2, 3, 4, 5])
y = np.array([1, 3, 2, 3, 1])

fig = go.Figure()
fig.add_trace(go.Scatter(x=x, y=y, name="linear",
                    line_shape='linear'))
fig.add_trace(go.Scatter(x=x, y=y + 5, name="spline",
                    text=["tweak line smoothness<br>with 'smoothing' in line object"],
                    hoverinfo='text+name',
                    line_shape='spline'))
fig.add_trace(go.Scatter(x=x, y=y + 10, name="vhv",
                    line_shape='vhv'))
fig.add_trace(go.Scatter(x=x, y=y + 15, name="hvh",
                    line_shape='hvh'))
fig.add_trace(go.Scatter(x=x, y=y + 20, name="vh",
                    line_shape='vh'))
fig.add_trace(go.Scatter(x=x, y=y + 25, name="hv",
                    line_shape='hv'))

fig.update_traces(hoverinfo='text+name', mode='lines+markers')
fig.update_layout(legend=dict(y=0.5, traceorder='reversed', font_size=16))

fig.show()

Label Lines with Annotations

In [9]:
import plotly.graph_objects as go
import numpy as np

title = 'Main Source for News'
labels = ['Television', 'Newspaper', 'Internet', 'Radio']
colors = ['rgb(67,67,67)', 'rgb(115,115,115)', 'rgb(49,130,189)', 'rgb(189,189,189)']

mode_size = [8, 8, 12, 8]
line_size = [2, 2, 4, 2]

x_data = np.vstack((np.arange(2001, 2014),)*4)

y_data = np.array([
    [74, 82, 80, 74, 73, 72, 74, 70, 70, 66, 66, 69],
    [45, 42, 50, 46, 36, 36, 34, 35, 32, 31, 31, 28],
    [13, 14, 20, 24, 20, 24, 24, 40, 35, 41, 43, 50],
    [18, 21, 18, 21, 16, 14, 13, 18, 17, 16, 19, 23],
])

fig = go.Figure()

for i in range(0, 4):
    fig.add_trace(go.Scatter(x=x_data[i], y=y_data[i], mode='lines',
        name=labels[i],
        line=dict(color=colors[i], width=line_size[i]),
        connectgaps=True,
    ))

    # endpoints
    fig.add_trace(go.Scatter(
        x=[x_data[i][0], x_data[i][-1]],
        y=[y_data[i][0], y_data[i][-1]],
        mode='markers',
        marker=dict(color=colors[i], size=mode_size[i])
    ))

fig.update_layout(
    xaxis=dict(
        showline=True,
        showgrid=False,
        showticklabels=True,
        linecolor='rgb(204, 204, 204)',
        linewidth=2,
        ticks='outside',
        tickfont=dict(
            family='Arial',
            size=12,
            color='rgb(82, 82, 82)',
        ),
    ),
    yaxis=dict(
        showgrid=False,
        zeroline=False,
        showline=False,
        showticklabels=False,
    ),
    autosize=False,
    margin=dict(
        autoexpand=False,
        l=100,
        r=20,
        t=110,
    ),
    showlegend=False,
    plot_bgcolor='white'
)

annotations = []

# Adding labels
for y_trace, label, color in zip(y_data, labels, colors):
    # labeling the left_side of the plot
    annotations.append(dict(xref='paper', x=0.05, y=y_trace[0],
                                  xanchor='right', yanchor='middle',
                                  text=label + ' {}%'.format(y_trace[0]),
                                  font=dict(family='Arial',
                                            size=16),
                                  showarrow=False))
    # labeling the right_side of the plot
    annotations.append(dict(xref='paper', x=0.95, y=y_trace[11],
                                  xanchor='left', yanchor='middle',
                                  text='{}%'.format(y_trace[11]),
                                  font=dict(family='Arial',
                                            size=16),
                                  showarrow=False))
# Title
annotations.append(dict(xref='paper', yref='paper', x=0.0, y=1.05,
                              xanchor='left', yanchor='bottom',
                              text='Main Source for News',
                              font=dict(family='Arial',
                                        size=30,
                                        color='rgb(37,37,37)'),
                              showarrow=False))
# Source
annotations.append(dict(xref='paper', yref='paper', x=0.5, y=-0.1,
                              xanchor='center', yanchor='top',
                              text='Source: PewResearch Center & ' +
                                   'Storytelling with data',
                              font=dict(family='Arial',
                                        size=12,
                                        color='rgb(150,150,150)'),
                              showarrow=False))

fig.update_layout(annotations=annotations)

fig.show()

Filled Lines

In [10]:
import plotly.graph_objects as go
import numpy as np



x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
x_rev = x[::-1]

# Line 1
y1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
y1_upper = [2, 3, 4, 5, 6, 7, 8, 9, 10, 11]
y1_lower = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
y1_lower = y1_lower[::-1]

# Line 2
y2 = [5, 2.5, 5, 7.5, 5, 2.5, 7.5, 4.5, 5.5, 5]
y2_upper = [5.5, 3, 5.5, 8, 6, 3, 8, 5, 6, 5.5]
y2_lower = [4.5, 2, 4.4, 7, 4, 2, 7, 4, 5, 4.75]
y2_lower = y2_lower[::-1]

# Line 3
y3 = [10, 8, 6, 4, 2, 0, 2, 4, 2, 0]
y3_upper = [11, 9, 7, 5, 3, 1, 3, 5, 3, 1]
y3_lower = [9, 7, 5, 3, 1, -.5, 1, 3, 1, -1]
y3_lower = y3_lower[::-1]


fig = go.Figure()

fig.add_trace(go.Scatter(
    x=x+x_rev,
    y=y1_upper+y1_lower,
    fill='toself',
    fillcolor='rgba(0,100,80,0.2)',
    line_color='rgba(255,255,255,0)',
    showlegend=False,
    name='Fair',
))
fig.add_trace(go.Scatter(
    x=x+x_rev,
    y=y2_upper+y2_lower,
    fill='toself',
    fillcolor='rgba(0,176,246,0.2)',
    line_color='rgba(255,255,255,0)',
    name='Premium',
    showlegend=False,
))
fig.add_trace(go.Scatter(
    x=x+x_rev,
    y=y3_upper+y3_lower,
    fill='toself',
    fillcolor='rgba(231,107,243,0.2)',
    line_color='rgba(255,255,255,0)',
    showlegend=False,
    name='Fair',
))
fig.add_trace(go.Scatter(
    x=x, y=y1,
    line_color='rgb(0,100,80)',
    name='Fair',
))
fig.add_trace(go.Scatter(
    x=x, y=y2,
    line_color='rgb(0,176,246)',
    name='Premium',
))
fig.add_trace(go.Scatter(
    x=x, y=y3,
    line_color='rgb(231,107,243)',
    name='Ideal',
))

fig.update_traces(mode='lines')
fig.show()

Dash Example

Dash is an Open Source Python library which can help you convert plotly figures into a reactive, web-based application. Below is a simple example of a dashboard created using Dash. Its source code can easily be deployed to a PaaS.

In [11]:
from IPython.display import IFrame
IFrame(src= "https://dash-simple-apps.plotly.host/dash-lineplot/", width="100%", height="650px", frameBorder="0")
Out[11]:
In [12]:
from IPython.display import IFrame
IFrame(src= "https://dash-simple-apps.plotly.host/dash-lineplot/code", width="100%", height=500, frameBorder="0")
Out[12]:

Reference

See https://plot.ly/python/reference/#scatter for more information and chart attribute options!