Python Plotly - Changing color of font on annotation in heatmap

Question

I have a heatmap that I created with this code:

dfreverse = df_hml.values.tolist()
dfreverse.reverse()

colorscale = [[0, '#FFFFFF'],[0.4, '#F8F8FF'], [1, '#F1C40F']]

x = [threeYr,twoYr,oneYr,Yr]
y = ['March', 'February', 'January', 'December', 'November', 'October', 'September', 'August', 'July', 'June', 'May', 'April']
z = dfreverse

z_text = np.around(z, decimals=2) # Only show rounded value (full value on hover)

fig = ff.create_annotated_heatmap(z, x=x, y=y,annotation_text=z_text, colorscale=colorscale, hoverinfo='none')


# Altering x axis
fig['layout']['xaxis']['tickfont']['family'] = 'Gill Sans MT'
fig['layout']['xaxis']['tickfont']['size'] = 12
fig['layout']['xaxis']['tickfont']['color'] = "black"
fig['layout']['xaxis']['tickangle'] = 0

# Altering x axis
fig['layout']['yaxis']['tickfont']['family'] = "Gill Sans MT"
fig['layout']['yaxis']['tickfont']['size'] = 12
fig['layout']['yaxis']['tickfont']['color'] = "black"
fig['layout']['yaxis']['tickangle'] = 25

# Altering main font
fig['layout']['font'] ["family"] = "Gill Sans MT"
fig['layout']['font']['size'] = 9

plotly.offline.iplot(fig,config={"displayModeBar": False},show_link=False,filename='pandas-heatmap')

As you can see, August to March this year doesnt have any data and thus is showing as 0. I cant remove this otherwise the heatmap doesnt work... so I was thinking I would change the font of any 0's to white to hide them. However I am not sure how to do this.

I found this code which changes the fontsize of the annotation, but not sure how to alter it to change the color if the value == 0 (as 'i' is not the value)

for i in range(len(fig.layout.annotations)):
         fig.layout.annotations[i].font.size = 9

Naren Murali · Accepted Answer · 2017-08-16 17:20:20Z

1

Instead of changing the annotation just loop through the z values and replace the 0 values with "". This is producing the same output. I have used some mockup data for simulating the issue.

Code:

import pandas as pd
import numpy as np
import plotly.figure_factory as ff
import plotly.offline as py_offline
py_offline.offline.init_notebook_mode()
colorscale = [[0, '#FFFFFF'],[0.4, '#F8F8FF'], [1, '#F1C40F']]

x = ['2015','2016','2017','2018']
y = ['March', 'February', 'January','April']
z = [[1,2.129,3,4],
    [0,0,1,2],
    [6,0,1,0],
    [6,0,0,2]]

z_text = []

for q, arr in enumerate(np.around(z, decimals=2)):
    z_text.append([str(h) if h else "" for h in arr])

fig = ff.create_annotated_heatmap(z, x=x, y=y,annotation_text=z_text, colorscale=colorscale, hoverinfo='none')


# Altering x axis
fig['layout']['xaxis']['tickfont']['family'] = 'Gill Sans MT'
fig['layout']['xaxis']['tickfont']['size'] = 12
fig['layout']['xaxis']['tickfont']['color'] = "black"
fig['layout']['xaxis']['tickangle'] = 0

# Altering x axis
fig['layout']['yaxis']['tickfont']['family'] = "Gill Sans MT"
fig['layout']['yaxis']['tickfont']['size'] = 12
fig['layout']['yaxis']['tickfont']['color'] = "black"
fig['layout']['yaxis']['tickangle'] = 25

# Altering main font
fig['layout']['font'] ["family"] = "Gill Sans MT"
fig['layout']['font']['size'] = 9

py_offline.iplot(fig,config={"displayModeBar": False},show_link=False,filename='pandas-heatmap')

Output:

answered Aug 16, 2017 at 17:20

Naren Murali

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2 Comments

Nicholas Over a year ago

Hey Naren again :)... I will test this tomorrow morning as I am not at work, but your solution makes a lot more sense than what I was trying to do!

Naren Murali Over a year ago

@ScoutEU no problem take your time

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