numpy - Python count and probability -

i have following data :

name    item peter   apple peter   apple ben     banana peter   banana 

i want print

frequency of peter eat : apple 2  banana 1  

this code

u, count = np.unique(data['item'], return_counts=true)  process = u[np.where(data['name']= 'peter')[0]]  process2 = dict(counter(process)) print "item\frequency"  k, v in process2.items(): print '{0:.0f}\t{1}'.format(k,v) 

but got error want calculate probability of peter eat apple next time dont have idea , suggestion ?

the error getting other answer indicates, cannot use data['name'] = 'peter' function parameter, intended use - np.where(data['name'] == 'peter') .

but, given using pandas , , guessing data pandas dataframe . in case, want can achieved using dataframe.groupby. example -

data[data['name']=='peter'].groupby('item').count() 

demo -

in [7]: data[data['name']=='peter'].groupby('item').count() out[7]:         name item apple      2 banana     1 

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if want printed in loop, can use -

df = data[data['name']=='peter'].groupby('item').count() fruit,count in df['name'].iteritems():     print('{0}\t{1}'.format(fruit,count)) 

demo -

in [24]: df = data[data['name']=='peter'].groupby('item').count()  in [25]: fruit,count in df['name'].iteritems():    ....:     print('{0}\t{1}'.format(fruit,count))    ....: apple   2 banana  1 

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for updated issue op getting, getting following error -

typeerror: invalid type comparison

the issue occurs in case because in real data op , column has numeric values (float/int) , op comparing values against string, , hence getting error. example -

in [30]: df out[30]:    0  1 0  1  2  in [31]: df[0]=='asd' --------------------------------------------------------------------------- typeerror                                 traceback (most recent call last) <ipython-input-31-e7bacd79d320> in <module>() ----> 1 df[0]=='asd'  c:\anaconda3\lib\site-packages\pandas\core\ops.py in wrapper(self, other, axis)     612     613             # scalars --> 614             res = na_op(values, other)     615             if np.isscalar(res):     616                 raise typeerror('could not compare %s type series'  c:\anaconda3\lib\site-packages\pandas\core\ops.py in na_op(x, y)     566                 result = getattr(x, name)(y)     567                 if result notimplemented: --> 568                     raise typeerror("invalid type comparison")     569             except (attributeerror):     570                 result = op(x, y)  typeerror: invalid type comparison 

if column numeric, should compare against numeric values, not string.