您如何找到字典的平均值？

Question

So let's say I have this dictionary

{'Taylor Swift': ['Kanye West']}

I would expect 1.0 from this as there is one value (which is 'Kanye West') divided by one key (which is 'Taylor Swift') to get the average of 1.0.

And let's say I have this dictionary

{'Taylor Swift': ['Kanye West', 'Elvis Presley'], 'Adam Sandler': ['Johnny Depp', 'Tom Hanks']}

I would expect the average of 2.0 from this as there are 4 values divided by 2 keys.

This is the code I have tried:

average = 0
sum = 0
for n in data:
    sum = sum + n
average = sum / len(data)

I have tried many other ways too through online search and the common error I get is this:

TypeError: unsupported operand type(s) for +: 'int' and 'str'

Answer 1

Taking "average" as "the average number of items in the lists", you can achieve it as:

average_length = sum( len(v) for v in data.values() ) / len(data)

The first part adds together the length of all the lists you have as dictionary values, while len(data) is the number of key:value pair you have in the dictionary.

Answer 2

Try this

average = 0
sum = 0
for key in data.keys():
    sum = sum +len(data[key])
average = sum / len(data)

Answer 3

 average = 0
 sum = 0
 for v in data.values():
      sum = sum + len(v)

 average = sum / len(data.keys())

Answer 4

Use simple for loop

var= {'Taylor Swift': ['Kanye West', 'Elvis Presley'], 'Adam Sandler': 
['Johnny Depp', 'Tom Hanks']}

sum = 0
for value in var.values():
    sum = len(value)+sum

Average = sum/len(var)
print(Average)

Output

2.0

Answer 5

Could use reduce here too:

from functools import reduce
data = {'Taylor Swift': ['Kanye West', 'Elvis Presley'], 'Adam Sandler': ['Johnny Depp', 'Tom Hanks']}
reduce((lambda x, y: len(x)+len(y)), data .values()) / len(data )

Answer 6

Get the length of values first and divide it by the length of keys.

sum(len(i) for i in data.values())/float(len(data.keys()))

and this gives the same result as well,

sum(len(i) for i in x.values())/float(len(x))

Answer 7

Here you go

#some dictionary
d={'Taylor Swift': ['Kanye',' West', 'Elvis',' Presley','l'], 'Adam Sandler': ['Johnny',' Depp', 'Tom',' Hanks']}
#Sum function gets the sum of all values in dictionary
#Len function gets the total number of keys in dictionary
#Multiplying with 1.0 to get exact division, else import division function from _future_ library 
avg = sum(len(v) for v in d.itervalues())*1.0/len(d)
print avg