I'm trying to slice into a multi-indexed data frame. I'm confused about conditions that generate IndexingError: Too many indexers. I'm also skeptical because I've found some bug reports about what may be this issue.
Specifically, this generates the error:
idx1 = [str(elem) for elem in [5, 6, 7, 8]]
idx2 = [str(elem) for elem in [10, 20, 30]]
index = pd.MultiIndex.from_product([idx1, idx2], names=('idx1', 'idx2'))
columns = ['m1', 'm2', 'm3']
df = pd.DataFrame(index=index, columns= columns)
df['m1'].loc[:,10]
That code above is trying to index into an index of dtypes of str, with an int, it seems to me. The error threw me off, as I don't understand why it says Too many indexers.
The below code works:
idx1 = [5, 6, 7, 8]
idx2 = [10, 20, 30]
index = pd.MultiIndex.from_product([idx1, idx2], names=('idx1', 'idx2'))
columns = ['m1', 'm2', 'm3']
df = pd.DataFrame(index=index, columns= columns)
df.loc[5,10] = [1,2,3]
df.loc[6,10] = [4,5,6]
df.loc[7,10] = [7,8,9]
type(df2['m1'])
df['m1'].loc[:,10]
There are some references to the same error: https://github.com/pandas-dev/pandas/issues/13597 which is marked closed and https://github.com/pandas-dev/pandas/issues/14885 which is open. Is it ok to slice (a multi-indexed series) as in the lines above, assuming I get the dtype right? Also "Too many indexers" with DataFrame.loc
My pandas version is 20.3.
