大文件中每个人的唯一值总数

Question

I have this unique list:

unique_list = {'apple', 'banana', 'coconut'}

I want to find how many of the elements occur exactly in my large text file. I just need the number, not the names. For example, if only 'apple' and 'banana' are found for a particular person, then it should return 2.

For each person (name and family name), I need to get how many of these unique fruit does this person have. In a large file, this might be difficult. I need the fastest way to do it.

Let's say I get names from the text file:

people = {'cody meltin', 'larisa harris', 'harry barry'}

The text file is as below:

Name           Fruit unit

cody melton    apple  3

cody melton    banana 5

cody melton    banana 7

larisa harris  apple  8

larisa harris  apple  5

The output should look like this:

{'cody meltin':2, 'larisa harris':1, 'harry barry':0}

I do not want to use any packages, just built-ins and basic libraries.

Answer 1

you can leverage python's basic library - collections

from collections import Counter

dict(Counter(pd.Series(['cody', 'cody ', 'cody ', 'melton', 'melton', 'harry'])))

Output

{'cody ': 2, 'melton': 2, 'cody': 1, 'harry': 1}

In my example above, I passed a pd.Series as its argument, but in your case, you can pass df['name'] to it, which is a pd.Series object.

Answer 2

You don't specify what is the format of your source data, so let's say it's a list of lists:

>>> data = [["cody melton", "apple", 3], ["cody melton", "banana", 5],
            ["cody melton", "banana", 7], ["larisa harris", "apple", 8],
            ["larisa harris", "apple", 5]]

When you are looking for performance in the "vanilla" python, look at the standard library - in this case collections.Counter ; we'll use it to count all unique combos of name-fruit:

>>> pairs = Counter(((x[0], x[1]) for x in data))
>>> pairs
Counter({('cody melton', 'banana'): 2, ('larisa harris', 'apple'): 2, ('cody melton', 'apple'): 1})

The argument is an iterator, that creates a tuple (name, fruit) out of the source data, and Counter does the counting of their occurrence.

---

EDIT: And if you want to count only the ones where the fruit is in a specific set:

fruits = set(['apple', 'banana', 'coconut'])

, then just add this as a condition in the comprehension:

>>> pairs = Counter(((x[0], x[1]) for x in data if x[1] in fruits))

---

We're almost there - what is left is to count the occurrences of the individual names:

>>> names = Counter((pair[0] for pair in pairs))
>>> names
Counter({'cody melton': 2, 'larisa harris': 1})
>>> dict(names)  # this is how to cast it to a regular dict
{'larisa harris': 1, 'cody melton': 2}

I see you have in your output a "harry barry" with 0 occurrences- they obviously did not appear in the source data , so just add them to the dict with value 0.

Answer 3

Just do it:

xx = ['apple', 'apple', 'banana', 'coconut'];
d = dict()

for x in xx:    
    if x in d:
        d[x] += 1
    else:
        d[x] = 1


print (d)