CODEWITHSUNDEEP
pythonplotlylabelplotly-python
emil banning
emil banning

Reputation: 615

How to change variable/label names for the legend in a plotly express line chart

I want to change the variable/label names in plotly express in python. I first create a plot:

import pandas as pd
import plotly.express as px

d = {'col1': [1, 2, 3], 'col2': [3, 4, 5]}
df = pd.DataFrame(data=d)
fig = px.line(df, x=df.index, y=['col1', 'col2'])
fig.show()

Which yields:

enter image description here

I want to change the label names from col1 to hello and from col2 to hi. I have tried using labels in the figure, but I cannot get it to work:

fig = px.line(df, x=df.index, y=['col1', 'col2'], labels={'col1': "hello", 'col2': "hi"})
fig.show()

But this seems to do nothing, while not producing an error. Obviously I could achieve my goals by changing the column names, but the actual plot i'm trying to create doesn't really allow for that since it comes from several different dataframes.

Upvotes: 55

Views: 98258

Answers (5)

vestland
vestland

Reputation: 61204

The answer:

Without changing the data source, a complete replacement of names both in the legend, legendgroup and hovertemplate will require:

newnames = {'col1':'hello', 'col2': 'hi'}
fig.for_each_trace(lambda t: t.update(name = newnames[t.name],
                                      legendgroup = newnames[t.name],
                                      hovertemplate = t.hovertemplate.replace(t.name, newnames[t.name])
                                     )
                  )

Plot:

enter image description here

The details:

Using

fig.for_each_trace(lambda t: t.update(name = newnames[t.name]))

...you can change the names in the legend without changing the source by using a dict

newnames = {'col1':'hello', 'col2': 'hi'}

...and map new names to the existing col1 and col2 in the following part of the figure structure (for your first trace, col1):

{'hovertemplate': 'variable=col1<br>index=%{x}<br>value=%{y}<extra></extra>',
'legendgroup': 'col1',
'line': {'color': '#636efa', 'dash': 'solid'},
'mode': 'lines',
'name': 'hello',   # <============================= here!
'orientation': 'v',
'showlegend': True,
'type': 'scatter',
'x': array([0, 1, 2], dtype=int64),
'xaxis': 'x',
'y': array([1, 2, 3], dtype=int64),
'yaxis': 'y'},

But as you can see, this doesn't do anything with 'legendgroup': 'col1', nor 'hovertemplate': 'variable=col1<br>index=%{x}<br>value=%{y}<extra></extra>' And depending on the complexity of your figure, this can pose a problem. So I would add legendgroup = newnames[t.name] and hovertemplate = t.hovertemplate.replace(t.name, newnames[t.name])into the mix.

Complete code:

import pandas as pd
import plotly.express as px
from itertools import cycle

d = {'col1': [1, 2, 3], 'col2': [3, 4, 5]}
df = pd.DataFrame(data=d)
fig = px.line(df, x=df.index, y=['col1', 'col2'])

newnames = {'col1':'hello', 'col2': 'hi'}
fig.for_each_trace(lambda t: t.update(name = newnames[t.name],
                                      legendgroup = newnames[t.name],
                                      hovertemplate = t.hovertemplate.replace(t.name, newnames[t.name])
                                     )
                  )

Upvotes: 58

Ruwan Pathirana
Ruwan Pathirana

Reputation: 157

import pandas as pd
import plotly.express as px

d = {'col1': [1, 2, 3], 'col2': [3, 4, 5]}
df = pd.DataFrame(data=d)
fig = px.line(df, x=df.index, y=['col1', 'col2'])

After you need to create dictionary called 'new' (custom name) and map the orginal trace names to custom names.

new = {'col1':'Front hello', 'col2': 'hi'}
fig.for_each_trace(lambda t: t.update(name = new[t.name]))
fig.show()

enter image description here

Upvotes: 1

callmeanythingyouwant
callmeanythingyouwant

Reputation: 2007

If you're looking for something even more concise, this function does the job-

def custom_legend_name(new_names):
    for i, new_name in enumerate(new_names):
        fig.data[i].name = new_name

Then before fig.show(), just pass a list consisting of the names you want, to the function, like this custom_legend_name(['hello', 'hi'])

Here's what the complete code would look like-

def custom_legend_name(new_names):
    for i, new_name in enumerate(new_names):
        fig.data[i].name = new_name
        

import pandas as pd
import plotly.express as px

d = {'col1': [1, 2, 3], 'col2': [3, 4, 5]}
df = pd.DataFrame(data=d)
fig = px.line(df, x=df.index, y=['col1', 'col2'])
custom_legend_name(['hello','hi'])
fig.show()

Upvotes: 1

Andi
Andi

Reputation: 4899

This piece of code is more concise.

import pandas as pd
import plotly.express as px

df = pd.DataFrame(data={'col1': [1, 2, 3], 'col2': [3, 4, 5]})

series_names = ["hello", "hi"]

fig = px.line(data_frame=df)

for idx, name in enumerate(series_names):
    fig.data[idx].name = name
    fig.data[idx].hovertemplate = name

fig.show()

Upvotes: 17

Nic Scozzaro
Nic Scozzaro

Reputation: 7373

Add the "name" parameter: go.Scatter(name=...)

Source https://plotly.com/python/figure-labels/

fig = go.Figure()

fig.add_trace(go.Scatter(
    x=[0, 1, 2, 3, 4, 5, 6, 7, 8],
    y=[0, 1, 2, 3, 4, 5, 6, 7, 8],
    name="Name of Trace 1"       # this sets its legend entry
))


fig.add_trace(go.Scatter(
    x=[0, 1, 2, 3, 4, 5, 6, 7, 8],
    y=[1, 0, 3, 2, 5, 4, 7, 6, 8],
    name="Name of Trace 2"
))

fig.update_layout(
    title="Plot Title",
    xaxis_title="X Axis Title",
    yaxis_title="X Axis Title",
    legend_title="Legend Title",
    font=dict(
        family="Courier New, monospace",
        size=18,
        color="RebeccaPurple"
    )
)

fig.show()

enter image description here

Upvotes: 36

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