with statement
In some cases, when writing big programs, we might forget to close the files. Manually opening and closing them seems like a lot of repetitive work. To avoid that issue, we can use
with statements to automatically open and close the file as soon as the program gets out of the with block:with open('document.txt') as f: # Previously f = open('document.txt')
print(f.read())
print('Done!')The
as keyword is used to create an alias. In this example, we create an alias f which refers to open('document.txt').Notice that there are no
f.open() calls or f.close() calls. That is handled automatically. As soon as the program enters the with open() block, the file document.txt is opened and as soon as the program gets out of the body of the with block, the file is closed. So, when the program reaches the statement print('Done!') the file has already been closed.This is the preferred way of working with files over
.open() and .close()-ing them every time.Challenge
You are asked to multiply two numbers located in the
numbers.txt file on separate lines.The output of the program should contain a single integer - the product of the two numbers.
numbers.txt | Output |
2
3 | 6 |
Constraints
Time limit: 2 seconds
Memory limit: 512 MB
Output limit: 1 MB