+ 4

Pls help me. With the logic

data={-1,1,2} def analyze(data): myData= data or '0' ans = [int(d) for d in myData] ans.sort(key = lambda x:(abs(x) , -x)) print(ans[0]) analyze(data)

8th Oct 2018, 5:33 AM
AMAN TOMAR
AMAN TOMAR - avatar
5 odpowiedzi
+ 5
data={-1,1,2} #data is a set with unique elements (unordered) myData= data or '0' #perform the operation on "data" or on 0 if "data" isn't specified ans = [int(d) for d in myData] #list comprehension: turn set into a list (could have just used list() instead, the int() isn't needed) ans.sort(key = lambda x:(abs(x) , -x)) #sort elements by their absolute value (that's why it needed to be converted into a list before, a set can't be sorted) print(ans[0]) #print first element (Sorry, I'm on my way to work ^^)
8th Oct 2018, 6:03 AM
Anna
Anna - avatar
+ 3
The lambda function returns a tuple of two numbers, abs(x) and -x. For 1 it returns (1, -1), for -1 it returns (1, 1). These numbers are used to sort the list. As long as the numbers in the list have different absolute values, only the first number of the tuple is used and the numbers are sorted by their absolute value in ascending order. As soon as they have the same absolute value like 1 and -1, the second value is used and they are sorted by their negative value. That's why 1 (negative value: -1) comes before -1 (negative value: 1).
10th Oct 2018, 5:03 AM
Anna
Anna - avatar
+ 2
8th Oct 2018, 5:34 AM
AMAN TOMAR
AMAN TOMAR - avatar
+ 2
thank u so much😁
8th Oct 2018, 6:05 AM
AMAN TOMAR
AMAN TOMAR - avatar
+ 1
I don't understand the lamdba function. What does (abs(x), -x) do? The sorted list seems to contain [1, -1, 2] but I simply can't figure out how it works, I can't even find this syntax with Google.
10th Oct 2018, 4:07 AM
Chris
Chris - avatar