Python sorting function

Question

em...I feel confused about this code, I am really new to coding, and wonder anyone can help:

def takeSecond(elem):# If I pass the argument as a list, why don't I need to specify it here? 
     return elem[1]  # what return elem[1] means,does it return the y in (x,y)? but why!?
random = [(2, 2), (3, 4), (4, 1), (1, 3)]
random.sort(key=takeSecond) # key = takeSecond what is this even mean lol?..
print('Sorted list:', random)

@yifeipeng--people are generally encouraged to be helpful to new users. Here's more explanation on how the sort key works — DarrylG
– DarrylG, Commented Jan 13, 2020 at 5:42

user12520850 · Accepted Answer · 2020-01-13 05:42:39Z

1

Let's say you have a list of items, which contains:

list = [a,b,c]

If you use the following piece of code:

def func():
    return list[1]

You'd get "b" as output. The number "1" is not the first element, it's the second element. The counting in python starts at 0. So basically, if you want to access "a", you have to use:

def func():
    return list[0]

Because 0 = a, 1 = b, 2 = c, and so on. If you change return elem[1] to return elem[0] you get the variable x.

answered Jan 13, 2020 at 5:42

user12520850

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Comments

Anbu · Accepted Answer · 2020-01-13 05:48:03Z

1

Here your trying to sort based on second value in given list
takeSecond function is always returns the second value in the given element.
In random.sort() method calling with your passing key parameter as takeSecond function, which means sorting perform based on that element it happen. In our case it will return second element. So sorting is perform based on second element
And then printing the sorted list

edited Jan 13, 2020 at 5:48

answered Jan 13, 2020 at 5:42

Anbu

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