What is the point of float('inf') in Python?

Question

Just wondering over here, what is the point of having a variable store an infinite value in a program? Is there any actual use and is there any case where it would be prefer

Answer 1

Instead of using 0 and then you need to handle negative numbers if there is any, float("+inf") and float("-inf") help compare positive or negative infinity like:

Find the largest value in a dictionary:

def max_key(my_dict):
    largest_key = float("-inf")
    largest_value = float("-inf")

    for key, value in my_dict.items():
      if value > largest_value:
          largest_value = value
          largest_key = key
    return largest_key


print(max_key({1:100, 2:1, 3:4, 4:10}))      # should print 1

print(max_key({"a":100, "b":10, "c":1000}))  # should print "c"