Format y axis as percent

Question

I have an existing plot that was created with pandas like this   df  myvar   plot kind  bar     The y axis is format as float and I want to change the y axis to percentages   All of the solutions I found use ax xyz syntax and I can only place code below the line above that creates the plot  I cannot add ax ax to the line above     How can I format the y axis as percentages without changing the line above   Here is the solution I found but requires that I redefine the plot   import matplotlib pyplot as plt import numpy as np import matplotlib ticker as mtick  data    8 12 15 17 18 18 5  perc   np linspace 0 100 len data    fig   plt figure 1   7 4   ax   fig add subplot 1 1 1   ax plot perc  data   fmt      0f      Format you want the ticks  e g   40   xticks   mtick FormatStrFormatter fmt  ax xaxis set major formatter xticks   plt show     Link to the above solution  Pyplot  using percentage on x axis

User · Accepted Answer

This is a few months late  but I have created PR 6251 with matplotlib to add a new PercentFormatter class  With this class you just need one line to reformat your axis  two if you count the import of matplotlib ticker    import     import matplotlib ticker as mtick  ax   df  myvar   plot kind  bar   ax yaxis set major formatter mtick PercentFormatter      PercentFormatter   accepts three arguments  xmax  decimals  symbol  xmax allows you to set the value that corresponds to 100  on the axis  This is nice if you have data from 0 0 to 1 0 and you want to display it from 0  to 100   Just do PercentFormatter 1 0    The other two parameters allow you to set the number of digits after the decimal point and the symbol  They default to None and      respectively  decimals None will automatically set the number of decimal points based on how much of the axes you are showing   Update  PercentFormatter was introduced into  Matplotlib proper in version 2 1 0

User · Answer

I propose an alternative method using seaborn   Working code    import pandas as pd import seaborn as sns data np random rand 10 2  100 df   pd DataFrame data  columns   A    B    ax  sns lineplot data df  markers  True  ax set xlabel  xlabel   ylabel  ylabel   title  title    changing ylables ticks y value       2f   format x        for x in ax get yticks    ax set yticklabels y value

User · Answer

Jianxun s solution did the job for me but broke the y value indicator at the bottom left of the window    I ended up using FuncFormatterinstead  and also stripped the uneccessary trailing zeroes as suggested here    import pandas as pd import numpy as np from matplotlib ticker import FuncFormatter  df   pd DataFrame np random randn 100 5    ax   df plot   ax yaxis set major formatter FuncFormatter lambda y         0    format y       Generally speaking I d recommend using FuncFormatter for label formatting  it s reliable  and versatile

User · Answer

pandas dataframe plot will return the ax for you  And then you can start to manipulate the axes whatever you want   import pandas as pd import numpy as np  df   pd DataFrame np random randn 100 5      you get ax from here ax   df plot   type ax     matplotlib axes  subplots AxesSubplot    manipulate vals   ax get yticks   ax set yticklabels       2    format x  for x in vals

User · Answer

I m late to the game but I just realize this  ax can be replaced with plt gca   for those who are not using axes and just subplots  Echoing  Mad Physicist answer  using the package PercentFormatter it would be  import matplotlib ticker as mtick  plt gca   yaxis set major formatter mtick PercentFormatter 1    if you already have ticks in the 0 to 1 range  Otherwise see their answer

User · Answer

For those who are looking for the quick one-liner   plt gca   set yticklabels      0f    format x 100  for x in plt gca   get yticks        Or if you are using Latex as the axis text formatter  you have to add one backslash      plt gca   set yticklabels      0f     format x 100  for x in plt gca   get yticks

User · Answer

Based on the answer of  erwanp  you can use the  formatted string literals of Python 3  x    2  percentage   f  x      2   inside the FuncFormatter   and combined with a lambda expression  All wrapped  ax yaxis set major formatter FuncFormatter lambda y     f  y

[python] Format y axis as percent

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