Seaborn heatmap showing incorrect x-axis values

Question

I have a Pandas dataframe ("df") that looks something like:

      Variable1    Var2         Parameters           Values
0        10.000     1.1           0.296342         0.170009   
1        10.015     1.1           0.297013         0.168656   
2        10.030     1.1           0.297659         0.167326   
3        10.045     1.1           0.298282         0.166018   
4        10.060     1.1           0.298883         0.164731   
5        10.075     1.1           0.299462         0.162223
...         ...     ...                ...              ...
4038     24.565     1.0           0.563698         0.222069

Pivoting the dataframe using the following commands,

# Pivot dataframe
df = df.pivot('Var2', 'Variable1', 'Values')

I get the below pivoted dataframe:

Variable1    10.000    10.015    10.030    10.045    10.060    10.075  \
Var2                                                                  
1.0        0.219987  0.218130  0.216290  0.214465  0.212654  0.210856   
1.1        0.170009  0.168656  0.167326  0.166018  0.164731  0.163467   
1.2        0.133185  0.132202  0.131230  0.130269  0.129318  0.128378   
1.3        0.104472  0.103893  0.103312  0.102729  0.102147  0.101564   

Variable1    ...       24.865    24.880    24.895    24.910    24.925  
Var2         ...                
1.0          ...     0.212118  0.211691  0.211272  0.210860  0.210456     
1.1          ...     0.174883  0.174566  0.174257  0.173956  0.173662   
1.2          ...     0.147406  0.147154  0.146907  0.146664  0.146425   
1.3          ...     0.126780  0.126616  0.126456  0.126301  0.126150   

However, when I try to image this using Seaborn's heatmap with the commands:

# Pivot dataframe
df = df.pivot('Var2', 'Variable1', 'Values')

# Create heatmap
f, ax = plt.subplots(figsize=(20, 10))
sns.heatmap(df)
ax.xaxis.set_major_locator(ticker.MultipleLocator(20))
ax.xaxis.set_major_formatter(ticker.ScalarFormatter())
plt.show()

I am getting a plot that shows the indices of Variable1 (0,1,2,3,4,...) whereas I need it to display the values of Variable1 (10, 10.015, 10.030, 10.045, etc.). I have included an example to illustrate.

What am I missing?

Answer 1

Copying your sample data,

Variable1    Var2         Parameters           Values
    0        10.000     1.1           0.296342         0.170009   
    1        10.015     1.1           0.297013         0.168656   
    2        10.030     1.1           0.297659         0.167326   
    3        10.045     1.1           0.298282         0.166018   
    4        10.060     1.1           0.298883         0.164731   
    5        10.075     1.1           0.299462         0.162223
    4038     24.565     1.0           0.563698         0.222069

df = pd.read_clipboard()
df = df.pivot('Var2', 'Variable1', 'Values')

How df looks like:

Variable1    10.000    10.015    10.030    10.045    10.060    10.075  \
Var2                                                                    
1.0             NaN       NaN       NaN       NaN       NaN       NaN   
1.1        0.170009  0.168656  0.167326  0.166018  0.164731  0.162223   

Variable1    24.565  
Var2                 
1.0        0.222069  
1.1             NaN 

just using sns.heatmap(df) returns,