pandas sum
# select numeric columns and calculate the sums
sums = df.select_dtypes(pd.np.number).sum().rename('total')
# append sums to the data frame
df.append(sums)
# X MyColumn Y Z
#0 A 84.0 13.0 69.0
#1 B 76.0 77.0 127.0
#2 C 28.0 69.0 16.0
#3 D 28.0 28.0 31.0
#4 E 19.0 20.0 85.0
#5 F 84.0 193.0 70.0
#total NaN 319.0 400.0 398.0