# importing pandas module 
import pandas as pd 
    
# importing numpy module 
import numpy as np 
    
# making list of values 
values = [3, 4, np.nan, 7, 2, 0] 
    
# making series from list 
series = pd.Series(values) 
    
# calling method 
cummin = series.cummin() 
    
# display 
cummin

0    3.0
1    3.0
2    NaN
3    3.0
4    2.0
5    0.0
dtype: float64

3
3  (3<4)
NaN (Since NaN cannot be compared to integer values)
3  (3<7)
2  (2<3)
0  (0<2)

# importing pandas module 
import pandas as pd 
    
# importing numpy module 
import numpy as np 
    
# making list of values 
values = [12, 4, 33, np.nan, 0, 1, 76, 5] 
    
# making series from list 
series = pd.Series(values) 
    
# calling method 
cummin = series.cummin(skipna = False) 
    
# display 
cummin 

0    12.0
1     4.0
2     4.0
3     NaN
4     NaN
5     NaN
6     NaN
7     NaN
dtype: float64