How to get the minimum value between 2 conditions-CodePudding

Starts when the start column is True and ends when the end column is True.

The obtained result is assigned to the result column.

Input:

import pandas as pd
import numpy as np
A = [6, 12, 21, 15, 18, 19, 13, 9, 10, 50]
cond1 = [False, True, False, False, False, False, True, False, False, False]
cond2 = [False, False, False, True, False, False, False, False, True, False]
df = pd.DataFrame({'A' : A, 'start' : cond1, 'end' : cond2})

Expected Output

    A   start   end    result
0   6   FALSE   FALSE   
1   12  TRUE    FALSE   
2   21  FALSE   FALSE   
3   15  FALSE   TRUE    12
4   18  FALSE   FALSE   12
5   19  FALSE   FALSE   12
6   13  TRUE    FALSE   12
7   9   FALSE   FALSE   12
8   10  FALSE   TRUE    9
9   50  FALSE   FALSE   9

Index 3 calculates the minimum value from index 1 to index 3

Index 8 calculates the minimum value from index 6 to index 8

CodePudding user response：

We may need to create the groupby key with cumsum , then transform the min of each group and shift it

df.loc[df.end,'new'] = (df.groupby([df['start'].cumsum(),df['end'].cumsum()]).
                        A.transform('min').shift())
df['new'] = df['new'].ffill()
df
Out[333]: 
    A  start    end   new
0   6  False  False   NaN
1  12   True  False   NaN
2  21  False  False   NaN
3  15  False   True  12.0
4  18  False  False  12.0
5  19  False  False  12.0
6  13   True  False  12.0
7   9  False  False  12.0
8  10  False   True   9.0
9  50  False  False   9.0

CodePudding user response：

Here is a simple algorithem to slove your problem

import pandas as pd

A=[6,12,21,15,18,19,13,9,10,50]
cond1=[False,True,False,False,False,False,True,False,False,False]
cond2=[False,False,False,True,False,False,False,False,True,False]
result=[]
numbers =[]
index=0

for i in A:
    result.append("")

minimum=None;
while index<len(A):
    if (cond1[index]):
        while(not(cond2[index])):
            numbers.append(A[index])
            if (minimum != None):
                result[index]=minimum
            index  = 1
        minimum = min(numbers)
        result[index]=minimum
        numbers=[]
        if(i==index):
            index =1
    else:

        if (minimum != None):
            result[index]=minimum
        index =1

df=pd.DataFrame({'A':A,'start':cond1,'end':cond2,'result':result})
print(df)

OUTPUT

    A  start    end result
0   6  False  False       
1  12   True  False       
2  21  False  False       
3  15  False   True     12
4  18  False  False     12
5  19  False  False     12
6  13   True  False     12
7   9  False  False     12
8  10  False   True      9
9  50  False  False      9

Hope this will help you to get the result which you expected.