CODEWITHSUNDEEP
pythonlist
Parzival
Parzival

Reputation: 57

How to check the uniqueness of lists inside list?

I have this data:

[[prodcutname,price_rate,price,quantity]]

[['phone', '500', 450.0, 1], ['phone', '500', 2250.0, 5], ['camera', '200', 1080.0, 6], ['laptop', '600', 540.0, 1], ['laptop', '600', 540.0, 1],['laptop', '600', 540.0, 1]]

Now, what I need to do is create a new list with only unique elements(products), and add other values of the same product and put them into list. The ideal output would look like:

[['phone','500',2700,6],['camera','220',1080,6],....]

I tried doing this using -

unique_list = ['phone', '500', 450.0, 1]

big_list = []
mylist = []

for i in range(len(larger_list)):
    for j in range(1,len(larger_list)):
        if(larger_list[i][0]==larger_list[j][0]):
            # Getting the sum or prices and number
            #Sum of price
            larger_list[j][2]=larger_list[i][2]+larger_list[j][2]

            #Sum of number
            larger_list[j][3]=larger_list[i][3]+larger_list[j][3]

            #Adding into a new list
            unique_list[0]=larger_list[i][0]
            unique_list[1]=larger_list[i][1]
            unique_list[2]=larger_list[j][2]
            unique_list[3]=larger_list[j][3]

            mylist.append(unique_list)
            big_list.append(mylist)
            mylist = []

return big_list

But ran into a lot of error to no avail. I even tried by putting them into dictionary. How do I go about doing this in Python?

Upvotes: 2

Views: 95

Answers (3)

Ajax1234
Ajax1234

Reputation: 71451

You can use itertools.groupby in Python3:

import itertools
s = [['phone', '500', 450.0, 1], ['phone', '500', 2250.0, 5], ['camera', '200', 1080.0, 6], ['laptop', '600', 540.0, 1], ['laptop', '600', 540.0, 1],['laptop', '600', 540.0, 1]]
new_s = [(a, list(b)) for a, b in itertools.groupby(sorted(s, key=lambda x:x[0]), key=lambda x:x[0])]
final_s = [[a, b[0][1], *list(map(sum, list(zip(*[i[2:] for i in b]))))] for a, b in new_s]

Output:

[['camera', '200', 1080.0, 6], ['laptop', '600', 1620.0, 3], ['phone', '500', 2700.0, 6]]

Upvotes: 1

Poiz
Poiz

Reputation: 7617

A Dictionary in Python means fairly the same thing as the word Dictionary. This implies, You can so easily lookup the Value of any keyword using the Keyword directly. This is, unfortunately, not possible with a list since lists are numerically indexed. It is thus recommended to first Convert your list into a Dictionary for 2 reasons:
1: Easier Mapping of the given Data to Individual Keys.
2: Processing the Data-Values to obtain your desired result.

As the Result of the Print shows, it is now easier to access any data by using the Key (even within a loop). For example, to get the Price of Phones, You can simply do:
dictList['phone']['price'] which is much more easier than doing something like: flatList[0][2] which is really not so intuitive....

product_list    = [
    ['phone',  '500', 450.0,  1],
    ['phone',  '500', 2250.0, 5],
    ['camera', '200', 1080.0, 6],
    ['laptop', '600', 540.0,  1],
    ['laptop', '600', 540.0,  1],
    ['laptop', '600', 540.0,  1]
]

# CREATE A LIST OF DICTIONARY FROM GIVEN DATA FOR EASIER MAPPING
item        = ["product_name", "price_rate", "price", "quantity"]
dictList    = {}
for data in product_list:
    if data[0] not in dictList:
        dictList[data[0]]   = dict(zip(item, data))
    else:
        tmpD    = dict(zip(item, data))
        dictList[data[0]]["price"]      = float(dictList[data[0]]["price"]) + float(tmpD['price'])
        dictList[data[0]]["quantity"]   = float(dictList[data[0]]["quantity"]) + float(tmpD['quantity'])
        # dictList[data[0]]["price_rate"] = float(dictList[data[0]]["price_rate"]) + float(tmpD['price_rate'])

print(dictList)
## PRINTS:
## {
##  'phone':  {'product_name': 'phone',  'price_rate': '500', 'price': 2700.0, 'quantity': 6.0}, 
##  'camera': {'product_name': 'camera', 'price_rate': '200', 'price': 1080.0, 'quantity': 6}, 
##  'laptop': {'product_name': 'laptop', 'price_rate': '600', 'price': 1620.0, 'quantity': 3.0}
## }

However, if for any reason you need to have your Data as a List, it is also quite easier with a simple list composition like so:

item        = ["product_name", "price_rate", "price", "quantity"]
dictList    = {}
for data in product_list:
    if data[0] not in dictList:
        dictList[data[0]]   = dict(zip(item, data))
    else:
        tmpD    = dict(zip(item, data))
        dictList[data[0]]["price"]      = float(dictList[data[0]]["price"]) + float(tmpD['price'])
        dictList[data[0]]["quantity"]   = float(dictList[data[0]]["quantity"]) + float(tmpD['quantity'])
        # dictList[data[0]]["price_rate"] = float(dictList[data[0]]["price_rate"]) + float(tmpD['price_rate'])

arrayList   = [ list(dVal.values()) for dKey, dVal in dictList.items() ]
print(arrayList)
## PRINTS:
## [
##     ['phone',  '500', 2700.0, 6.0], 
##     ['camera', '200', 1080.0, 6], 
##     ['laptop', '600', 1620.0, 3.0]
## ]

Upvotes: 3

Dadep
Dadep

Reputation: 2788

you can build a dict :

>>> l
[['camera', '200', 1080.0, 6], ['laptop', '600', 540.0, 1], ['laptop', '600', 540.0, 1], ['laptop', '600', 540.0, 1], ['phone', '500', 450.0, 1], ['phone', '500', 2250.0, 5]]
>>> for i in l:
...     if i[0] in d:
...             d[i[0]].append(i[1:])
...     else:
...             d[i[0]]=[i[1:]]
... 
>>> d
{'phone': [['500', 450.0, 1], ['500', 2250.0, 5]], 'laptop': [['600', 540.0, 1], ['600', 540.0, 1], ['600', 540.0, 1]], 'camera': [['200', 1080.0, 6]]}

Upvotes: 0

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