compute the delta between two consecutive dates in number of Deaths for top 10 states in America

DeltaOfTwoDates.py

# top 10 states in America
'''['California',
 'Florida',
 'Georgia',
 'Illinois',
 'Massachusetts',
 'Michigan',
 'New Jersey',
 'New York',
 'Pennsylvania',
 'Texas']'''

COL_STATES = bar_plot_df['Province/State'].tolist()

mask_september = df['ObservationDate']>='09/01/2020'
COL_HEATMAP = ['Country/Region', 'Province/State', 'Deaths', 'Confirmed', 'ObservationDate' ]
all_delta_df = pd.DataFrame()
delta_df = pd.DataFrame()

for STATE in COL_STATES:
    mask_one_state = df['Province/State']==STATE
    delta_df = pd.DataFrame()
    delta_df = df[mask_one_state & mask_september][COL_HEATMAP]
    delta_df['Delta_Deaths_'+STATE] = delta_df.Deaths.diff()

    if STATE=='California':
        all_delta_df[['ObservationDate', 'Delta_Deaths_'+STATE]] = delta_df[['ObservationDate', 'Delta_Deaths_'+STATE]].copy()
    else:
        all_delta_df = pd.merge(all_delta_df, delta_df[['ObservationDate', 'Delta_Deaths_'+STATE]], how='left', on='ObservationDate')
    
COL_DELATA = all_delta_df.columns.tolist()
COL_DELATA.remove('ObservationDate')

all_delta_df.dropna(inplace=True)
all_delta_df[COL_DELATA] = all_delta_df[COL_DELATA].astype(int)