CODEWITHSUNDEEP
python-3.xmaxmin
query_question
query_question

Reputation: 35

How to print the max and min number of a Python console input?

Everyone,

the task is as follows: to write a program that prints the max and min number of a Python console input.

For example, we enter (the "5" above is "n" => the count of the numbers to be entered):

5
10
30
504
0
60

The Output should say:

Max number: 504
Min number: 0

Below is the solution - could someone please explain to me the definition of max_number = -sys.maxsize and min_number = sys.maxsize (why are both variables' values actually the opposite to their actual ones) along with the if conditional statement, how should the iterations go so that the output is correct?

import sys

n = int(input())
max_number = -sys.maxsize
min_number = sys.maxsize

for i in range(n):
    current_number = int(input())

    if current_number > max_number:
        max_number = current_number
    if current_number < min_number:
        min_number = current_number

print(f'Max number: {max_number}')
print(f'Min number: {min_number}')

Thanks!

Upvotes: 1

Views: 11669

Answers (5)

Suhas_Pote
Suhas_Pote

Reputation: 4580

Here is quick and easy solution

user_input = input("Enter the numbers separated by a space ").split()

int_list = list(map(int, user_input))

print ("Max number:",max(int_list), "\nMin number:",min(int_list))

# Output

Enter the numbers separated by a space 5 10 30 504 0 60
Max number: 504 
Min number: 0

You can complete the task with just 3 lines of code and here user no need to provide number of integers or count

Explanation to your Question:

import sys

max_number = -sys.maxsize
min_number = sys.maxsize
print(max_number, max_number)

# Output
-9223372036854775807 9223372036854775807

As you can see sys.maxmsize (9223372036854775807) is the greatest integer and sys.maxmsize(-9223372036854775807) is the smallest integer.

For first If condition you are considering smallest integer for comparison so that even smallest value will be stored as max value for first iteration and it gets updated as it find out greater value than that. In your example, 5 would be consider as max_number in first iteration of for loop

why? first iteration of for loop

if 5 > -9223372036854775807  # max_number = -9223372036854775807, current_number = 5 hence condition is true i.e. 5 > -9223372036854775807 
   max_number = 5            # max_number updated with 5

# max_number is 5 now

second iteration of for loop

if 10 > max_number   # max_number = 5, current_number = 10 hence 10 > 5 condition is true     
   max_number = 10   # max_number updated with 10

# max_number is 10 now

and so on...at the end 504 will remain max_number

For second If condition situation is exactly opposite

first iteration of for loop

if 5 < 9223372036854775807      # min_number = 9223372036854775807, current_number = 5 hence condition is true i.e. 5 < 9223372036854775807 
   min_number = 5               # min_number has become 5 now

# min_number is 5 now
.
.    # min_number we remain 5 for 2nd, 3rd and 4th iterations because 10, 30 and 504 are greater than 5 hence failed to satisfy if condition
.

fifth iteration of for loop

if 0 < min_number               # min_number = 5, current_number=0
   min_number = 0               # min_number has become 0 now

# min_number is 0 now

At the end 0 will remain min_number

Upvotes: 1

Conffusion
Conffusion

Reputation: 4475

For max_number, each iteration in the for loop will check if the newly entered number is larger then the max_number value. If so, this new value will become the max_number value. After all iterations are processed, the variable max_numbers holds the value of the largest number. To make sure the value entered in the first iteration always wins compared to the max_number current value, you initialize max_number with the lowest possible value (-sys.maxsize). This way any entered number will always be larger and thus will become the new value of max_number.

begin: max_number = -sys.max_number
IN=10    -> max_number = 10
IN=30    -> max_number = 30
IN=504   -> max_number = 504
IN=0     -> max_number = 504
IN=60    -> max_number = 504

The same logic is used for min_number but in the other direction: initialise it with the highest possible value so the value of the first iteration will always be smaller and win the comparison.

Upvotes: 0

Naveen Kumar
Naveen Kumar

Reputation: 184

You can do something like this

n = int(input())

numbers = []
for i in range(n):
    numbers.append(int(input()))

print(f'Max number: {max(numbers)}')
print(f'Min number: {min(numbers)}')

Upvotes: 1

difurious
difurious

Reputation: 1542

https://docs.python.org/3/library/sys.html

"sys.maxsize An integer giving the maximum value a variable of type Py_ssize_t can take. It’s usually 2**31 - 1 on a 32-bit platform and 2**63 - 1 on a 64-bit platform."

So you are initialising the largest and smallest possible integers so the comparison will be able to compare if numbers entered are smaller or larger than the possible maximum or minimum.

>>> -sys.maxsize
-9223372036854775807
>>> sys.maxsize
9223372036854775807
>>>

You want them to be the opposite for the initial loop, else you have nothing to compare against. So anything should be larger than the theoretical minimum and vice versa.

Upvotes: 0

Adrien Kaczmarek
Adrien Kaczmarek

Reputation: 550

sys.maxmsize is the greatest integer a variable can take.

Thus, the program first initialise the max_number to the smaller number possible. By doing, it is sure that it will not miss a number in the list.

Then, it goes inside the inputs and each time it sees a number greater than the actual max_number it updates the max_number.


That being said, the first update will **always** occurs for the first item in the loop (because all the number are greater than the smallest number).

It makes the opposite for the `min_number` (takes the greatest number and then go down).


Does this help you?

For more precision on sys.maxsize look at the docs:
https://docs.python.org/3/library/sys.html
(search for maxsize)

Upvotes: 0

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