Remove all rows until some value in a column is met using pandas-CodePudding

I have a pandas dataframe (called result), which looks something like this:

event_1	event_2	event_3
1	1	1
1	1	1
1	Del	1
1	1	1

And I would like to remove all the rows before the one in which there is the value Del. So that the result would look like this:

event_1	event_2	event_3
1	Del	1
1	1	1

I tried adapting some code I found in some other posts, but it doesn't seem to do the trick (it actually runs for a lot, and never stops to run).

result.groupby('event_1').apply(lambda x: x.loc[(x.event_2 == "Del").idxmax():,:]).reset_index(drop=True)

CodePudding user response：

You can use boolean slicing:

df[df['event_2'].eq('Del').cummax()]

CodePudding user response：

if we have 2 or more occurrences and if you want the last one to consider, you can try below :

Example :

A=[1,2,3,'del',5,6,7]
B=[1,2,3,4,5,6,7]
C=[1,2,'del',4,5,6,7]

df=pd.DataFrame([B,A,C]).T
df.columns=list('ABC')
df
    A   B   C
0   1   1   1
1   2   2   2
2   3   3   del
3   4   del 4
4   5   5   5
5   6   6   6
6   7   7   7

ind=df[df.eq('del').any(1)].index.max()
df=df.iloc[ind:].reset_index(drop=True)

    A   B   C
0   4   del 4
1   5   5   5
2   6   6   6
3   7   7   7