df.drop if it exists

Add parameter errors to DataFrame.drop:

errors : {‘ignore’, ‘raise’}, default ‘raise’

If ‘ignore’, suppress error and only existing labels are dropped.

df = df.drop(['row_num','start_date','end_date','symbol'], axis=1, errors="ignore")

Sample:

df = pd.DataFrame({'row_num':[1,2], 'w':[3,4]})
df = df.drop(['row_num','start_date','end_date','symbol'], axis=1, errors="ignore")
print (df)
   w
0  3
1  4