dic_1 = pd.DataFrame({'name': ['ram','shyam','mohan', 'kalpesh', 'suresh'],
'Age' : [15,30,40,50,60]})
df_1 = pd.DataFrame(dic_1)
df_1 ['group'] = np.array(np.random.randn(len(df_1['Age'])))
df_1.loc[df_1['Age'] < 20, 'group'] = "below twenty"
df_1.loc[20 <= df_1['Age'] < 30, 'group'] = "twenty to thrity"
df_1.loc[30 <= df_1['Age'] < 40, 'group'] = "thrity to forty"
df_1.loc[df_1['Age'] > 40, 'group'] = "above forty"
print (df_1)