What is the right method to read from input file and perform subtraction?

Question

I am a beginner computational thinking programmer and am doing some basic problems for Australian Informatics Olympiad practice problems.

Here's the link to the question

This is my code so far:

inputfile = open("sitin.txt", "r")
outputfile = open("sitout.txt", "w")

r = 0
s = 0
t = 0
sit = 0
stand = 0
seats_available = 0

#Reading integers from input file

r, s = map(int, inputfile.readline().split())
t = map(int, inputfile.readline().split())

#Conducting the operations

seats_available = r * s

if t > seats_available:
    sit = r*s
    stand = t - seats_available
else: 
    sit = t
    stand = 0


#Writing answer in the output file

outputfile.write(sit + "" + stand + "\n")

outputfile.close()
inputfile.close()

Here's the error I get:

Traceback (most recent call last):
  line 25, in <module>
    if t > seats_available:
TypeError: '>' not supported between instances of 'map' and 'int'

Any help would be much appreciated!

score 1 · Answer 1 · answered Jun 02 '22 at 06:23

1

this will result as expected

#example line: "2 3" => r = 2, s = 3
r, s = map(int, inputfile.readline().split())

the problem is in this line:

t = map(int, inputfile.readline().split())
# results t = iterator, it doesn't unpack the result
# this should fix the problem:
t = int(inputfile.readline().split()[0])

or

t,dummy = map(int, inputfile.readline().split())

answered Jun 02 '22 at 06:23

Jupri

345
1
6

3

Simpler: Avoid the `split()` and indexing (there's only one value there anyway) and just do `t = int(inputfile.readline())` (`int` ignores leading/trailing whitespace for you, so you don't even need to call `.strip()` or `.rstrip()` on it). – ShadowRanger Jun 02 '22 at 06:29

score 1 · Accepted Answer · answered Jun 02 '22 at 06:33

You should use with open structure to open files so you don't have to worry about closing them. Also, initializing the values with 0 is something that you don't have to do so I dropped that too. These few things make your code easier to read and less error prone.

You are getting the error because on the line for t there is only a single value, so it is not automatically unpacked like r and s.

# Reading integers from input file
with open("sitin.txt", "r") as inputfile:
    r, s = map(int, inputfile.readline().split())
    t = int(inputfile.readline().strip())

#Conducting the operations

seats_available = r * s

if t > seats_available:
    sit = r*s
    stand = t - seats_available
else: 
    sit = t
    stand = 0

#Writing answer in the output file

with open("sitout.txt", "w") as outputfile:
    outputfile.write(f"{sit} {stand}\n")

What is the right method to read from input file and perform subtraction?

2 Answers2