The dataframe below is a multi-indexed dataframe with hierarchical columns (df):
EMG Biofeedback
Time ID
delta theta alpha beta high beta gamma HeartRateVariabilty GSR
20170101 PD102 4 5 8 3 0 9 1 2
20170102 PD102 5 7 8 4 6 5 2 3
20170101 SS104-1 3 4 4 5 2 4 8 2
20170101 SS104 3 4 3 4 2 4 8 2
How can i drop all rows that contain '-' (a dash) in the index i.e drop SS104-1?