I'm new with pandas and information processing and I'm struggling to do one thing a little bit complex in my opinion. I'll show you an example.

Let's say that I have a DataFrame df as follows:

```
A B C
a 237 1 0
b 243 0 -10candy
c 243 0 -15candy
d 243 0 again
e 243 0 -15candy+10of30000
f 243 1 0
g 246 0 -10
h 246 0 -20candy+10of20
i 246 0 -10
j 246 1 0
h 248 0 newcandybagopened
i 248 1 0
j 260 0 candybag70with74%~andmaybemorespecialchars)
k 260 0 +20candyof30sunnyday
l 260 1 0
```

So, I would like to process the modifications on the quantity of the candies, I would like to create another column in which the candy substractions would be added. The column A represents a group, I only want to compute the substraction of each group. The column B represent where a group "ends":

```
A B C candy_substractions
a 237 1 0 0
b 243 0 -10candy 10
c 243 0 -15candy 25
d 243 0 again 25
e 243 0 -15candy+10of30000 40
f 243 1 0 40
g 246 0 -10 10
h 246 0 -20candy+10of20 30
i 246 0 -10 40
j 246 1 0 40
h 248 0 newcandybagopened 0
i 248 1 0 0
j 260 0 candybag70with74%~morespecialchars) 0
k 260 0 +20candyof30sunnyday 0
l 260 1 0 0
```

Also, I want to compute how many candies have been added to each group. There are several types of candies which I know and we can set that prior to the processing.

```
A B C candy_30000 candy_20000
a 237 1 0 0 0
b 243 0 -10candy 0 0
c 243 0 -15candy 0 0
d 243 0 again 0 0
e 243 0 -15candy+10of3000067 10 0
e' 243 0 +10of30000+5of20 20 5
f 243 1 0 20 5
g 246 0 -10 0 0
h 246 0 -20candy+10of20 0 10
i 246 0 -10 0 10
j 246 1 0 0 10
h 248 0 newcandybagopened 0 0
i 248 1 0 0 0
j 260 0 candybag70with74%~morespecialchars) 0 0
k 260 0 +20candyof30sunnyday 20 0
l 260 1 0 20 0
```

The problem here is that candies of type 20000 sometimes are written as 20, or maybe even 200. So I would like to have that in a set which I could modify easily. the same with the other candy type. It it's a substraction or an addition, it is always stated by it's arithmetic operators (-) and (+) respectively. There random numbers and messages I don't want to take into account. Like in row e or j.

Sorry but I have no idea from where to start. Any advices?

Thank you so much.

Read more here: https://stackoverflow.com/questions/66275783/how-to-process-information-on-one-column-and-then-build-a-logical-statement

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