When using the loc function in pandas dataFrame, as follows
df.loc[('M' in df.Name and df.P>1),'m']=1
df.loc[('M' not in df.Name or df.P < 1), 'm'] = 0
The following error occurred:
raise KeyError("cannot use a single bool to index into setitem")
KeyError: 'cannot use a single bool to index into setitem'The reason is that the logic operation is wrong and should be modified into the following form:
df.loc[('M' in df.Name) & (df.P>1),'m']=1
df.loc[('M' not in df.Name) | (df.P < 1), 'm'] = 0