matplotlib subplot axis label

Question

I have a subplot, its x-axis label uses voltages, its csv data column values increase from 0 to 30 and then decrease from 30 to 0. when I use this code it gives me this plot

ax2.plot(df_raw.index, df_raw.loc[:,"data_column"])

When I use below code I got the plot as as shown below

ax2.plot(df_raw.loc[:,"voltage"], df_raw.loc[:,"data_column"])

What I really want is as shown below

Answer 1

Try to set the label manually:

df = pd.DataFrame({'vol': list(range(101)) + list(range(99,0,-1)),
                   'val': [0]*10 + [1]*180 +[0]*10})

fig, ax = plt.subplots()
ax.plot(df.index, df.val)

ax.set_xticklabels(df.vol[ax.get_xticks()]
                 .fillna(0).astype(int))
plt.show()