CODEWITHSUNDEEP
pythonpandasnumpy
penguin
penguin

Reputation: 459

Slice pandas rows between two numpy arrays

I am looking to slice a Pandas dataframe according to values in a couple of pandas series.
So I need the rows in-between the values of the pandas series.
For example:

df = pd.DataFrame(np.random.rand(10,5), columns = list('abcde'))

enter image description here

df_info = pd.DataFrame(data= {'beginRows': [2, 7], 'endRows': [4, 9]}

enter image description here

I need the rows in df that are between the value of beginRows and endRows, in each row of df_info.
Technically, I can do this as: 

df_result = df[df.index.isin(np.r_[2:4+1,7:9+1])]

enter image description here

I am not sure how to make that list to send as a parameter to np.r_, from the df_info dataframe.
Thank you.

Upvotes: 1

Views: 406

Answers (1)

jpp
jpp

Reputation: 164773

You can pass slice objects:

slice1 = slice(2, 4+1)
slice2 = slice(7, 9+1)

df_result = df[df.index.isin(np.r_[slice1, slice2])]

Given your input df_info:

s1, s2 = [slice(i, j+1) for i, j in df_info.values]

df_result = df[df.index.isin(np.r_[s1, s2])]

Or, for an arbitrary number of slices, you can pass a tuple to np.r_.__getitem__:

slices = tuple(slice(i, j+1) for i, j in df_info.values)

df_result = df[df.index.isin(np.r_.__getitem__(slices))]

Upvotes: 2

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