CODEWITHSUNDEEP
pythonlistsorting
SammyHD
SammyHD

Reputation: 49

Sorting values in multiple lists

Currently, I have a list of lists called result which will contain values like this, for example:

result[1] = [John,  0.32]
result[2] = [Mikey, 1.90]
result[3] = [Sarah, 1.31]
result[4] = [Nancy, 0.49]
result[5] = [Billy, 0.13]

I want to however, sort this in descending order by the number which is held in the index space [1]. So the system will return the values in that order. Would I just have to use the sorted() function and call up the index where the value is held? I do not need to resort the list is it is necessary, i will just need to output the values in descending order.

How would I go about doing this exactly?

Upvotes: 1

Views: 49

Answers (2)

thefourtheye
thefourtheye

Reputation: 239443

Use the key parameter in the sorted function.

sorted(result, key = lambda x:x[1], reverse = True)

The reverse = True makes sure that the items are sorted in the descending order. The important thing to be noted here is the key parameter.

key = lambda x:x[1]

We pass a lambda function to the key parameter, which accepts one parameter. sorted picks each element from result and pass that to the key function. In our case it is the tuples. The key function returns the second item in the tuples. So, the second item in the tuple will be used as the value of the tuple itself, while sorting. It means that when we comapre [John, 0.32] and [Mikey, 1.90], we will be actually comparing 0.32 and 1.90 only.

sorted doesn't change the actual list, but creates a new sorted list. But, if you want to sort the list itself, then you can use list.sort method, like this

result.sort(key = lambda x:x[1], reverse = True)

Upvotes: 5

sshashank124
sshashank124

Reputation: 32189

You can do that using sorted:

new_list = sorted(old_list, key=lambda x: x[1], reverse=True)

or using sort:

old_list.sort(key=lambda x: x[1], reverse=True)

Upvotes: 0

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