f, (ax1, ax2) = plt.subplots(ncols=1, nrows=2, figsize=(16,8))
f.subplots_adjust(hspace=0.35)

weekdays_order =['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday',
'Saturday', 'Sunday']

ax1 = sns.barplot(x='weekday_number', y='Error_absoluto', data=df_1 , ax=ax1)
ax2 = sns.barplot(x='weekday', y='Error_absoluto', data=df_2, ax=ax2)

ax2.set_xlabel('Weekday')
ax2.set_ylabel('Error')
ax1.set_xlabel('Weekday')
_ = ax1.set_ylabel('Error')