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Check if list has no duplicates

Checks if all the values in a list are unique.

Use set() on the given list to keep only unique occurrences.
Use len() to compare the length of the unique values to the original list.

def all_unique(lst):
  return len(lst) == len(set(lst))

x = [1, 2, 3, 4, 5, 6]
y = [1, 2, 2, 3, 4, 5]
all_unique(x) # True
all_unique(y) # False

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