Say I have the following dataframe (a column of integers and a column with a list of integers)...
ID Found_IDs
0 12345 [15443, 15533, 3433]
1 15533 [2234, 16608, 12002, 7654]
2 6789 [43322, 876544, 36789]
And also a separate list of IDs...
bad_ids = [15533, 876544, 36789, 11111]
Given that, and ignoring the df['ID'] column and any index, I want to see if any of the IDs in the bad_ids list are mentioned in the df['Found_IDs'] column. The code I have so far is:
df['bad_id'] = [c in l for c, l in zip(bad_ids, df['Found_IDs'])]
This works but only if the bad_ids list is longer than the dataframe and for the real dataset the bad_ids list is going to be a lot shorter than the dataframe. If I set the bad_ids list to only two elements...
bad_ids = [15533, 876544]
I get a very popular error (I have read many questions with the same error)...
ValueError: Length of values does not match length of index
I have tried converting the list to a series (no change in the error). I have also tried adding the new column and setting all values to False before doing the comprehension line (again no change in the error).
Two questions:
- How do I get my code (below) to work for a list that is shorter than a dataframe?
- How would I get the code to write the actual ID found
back to the
df['bad_id']column (more useful than True/False)?
Expected output for bad_ids = [15533, 876544]:
ID Found_IDs bad_id
0 12345 [15443, 15533, 3433] True
1 15533 [2234, 16608, 12002, 7654] False
2 6789 [43322, 876544, 36789] True
Ideal output for bad_ids = [15533, 876544] (ID(s) are written to a new column or columns):
ID Found_IDs bad_id
0 12345 [15443, 15533, 3433] 15533
1 15533 [2234, 16608, 12002, 7654] False
2 6789 [43322, 876544, 36789] 876544
Code:
import pandas as pd
result_list = [[12345,[15443,15533,3433]],
[15533,[2234,16608,12002,7654]],
[6789,[43322,876544,36789]]]
df = pd.DataFrame(result_list,columns=['ID','Found_IDs'])
# works if list has four elements
# bad_ids = [15533, 876544, 36789, 11111]
# fails if list has two elements (less elements than the dataframe)
# ValueError: Length of values does not match length of index
bad_ids = [15533, 876544]
# coverting to Series doesn't change things
# bad_ids = pd.Series(bad_ids)
# print(type(bad_ids))
# setting up a new column of false values doesn't change things
# df['bad_id'] = False
print(df)
df['bad_id'] = [c in l for c, l in zip(bad_ids, df['Found_IDs'])]
print(bad_ids)
print(df)
Using np.intersect1d to get the intersect of the two lists:
df['bad_id'] = df['Found_IDs'].apply(lambda x: np.intersect1d(x, bad_ids))
ID Found_IDs bad_id
0 12345 [15443, 15533, 3433] [15533]
1 15533 [2234, 16608, 12002, 7654] []
2 6789 [43322, 876544, 36789] [876544]
Or with just vanilla python using intersect of sets:
bad_ids_set = set(bad_ids)
df['Found_IDs'].apply(lambda x: list(set(x) & bad_ids_set))