python 3.x - When a Pandas Data Frame is Subset, does it need to be reindex? -

i making multi-plot using pandas dataframe , matplotlib. however, when alter dataframe , remove 1 of items error:

valueerror: cannot reindex duplicate axis 

my initial code following , plots great, have group (plot) don't need:

branchgroups = alldata['branchgroupings'].unique()  fig2 = plt.figure(figsize = (15,15))  i,branchgroups in enumerate(branchgroups):     ax = plt.subplot(3,3,i+1)     idx = alldata['branchgroupings'] == branchgroups      kmf.fit(t[idx], c[idx], label=branchgroups)       kmf.plot(ax=ax, legend=false)     plt.title(branchgroups)     plt.xlabel('timeline in months')     plt.xlim(0,150)   fig2.tight_layout() fig2.suptitle('cumulative hazard function of employee groups', size = 16) fig2.subplots_adjust(top=0.88, hspace = .4) plt.show() 

in branchgroups there 7 items when print them out:

['branchmgr', 'banker', 'service', 'mdoandrsm', 'sbrmandbbrm','fc', 'de'] 

the code above makes 7 plots nicely, don't need 'de' grouping (one plot each of groups).

so, did drop of de performing following:

#remove de data set node = alldata[alldata.branchgroupings != 'de'] 

this drops 'de' categories , reduces number of rows. head(), , looks great; new data frame.

then, modifying plot give 6 groups , plot reduced data frame node, used same code name changes fig3 rather fig2 , changed idx idxx prevent overwriting, otherwise it's same except new data frame reference node:

groups = node['branchgroupings'].unique()  #new data frame node  fig3 = plt.figure(figsize = (15,15))  i,groups in enumerate(groups): ax = plt.subplot(3,2,i+1) idxx = node['branchgroupings'] == groups   #new idxx rather idx  kmf.fit(t[idxx], c[idxx], label=groups)   kmf.plot(ax=ax, legend=false) plt.title(groups) plt.xlabel('timeline in months') plt.xlim(0,150) if  ==0:     plt.ylabel('frac employed after $n$ months') if  ==3:     plt.ylabel('frac employed after $n$ months')  fig3.tight_layout() fig3.suptitle('survivability of branch employees', size = 16) fig3.subplots_adjust(top=0.88, hspace = .4) plt.show() 

except, error mentioned above

cannot reindex duplicate axis

and traceback shows associated line below:

kmf.fit(t[idxx], c[idxx], label=groups) 

most due re-assignment line above it:

idxx = node['branchgroupings'] == groups 

do need reset/drop or new data frame node reset this?

update - has been solved; not sure how 'pythonic' is, works:

okay, after more research on this, seems when slicing dataframe, there inheritance issue. found out post here.

initially, performing following:

node.index.is_unique returns false

to make clean slice following steps needed:

#create slice using .copy node = alldata[['prodcat', 'duration', 'observed', 'branchgroupings']].copy()  #remove de data set node = node.loc[node['branchgroupings'] != 'de'] #use .loc cleaner slice  #reset index unique node['index'] = np.arange(len(node)) node = node.set_index('index') 

now performing node.index.is_unique returns true , error gone.