Question

I’m just getting started with python. Can somebody interpret line 2 of the following code snippet? I don’t understand the `num` bit. I tried to replace the backtick character with a single tick ', but then it broke. Just a detailed explanation of that line would be great.

loop_count = 1000000
irn = ''.join([`num` for num in range(loop_count)])
number = int(irn[1]) * int(irn[10]) * int(irn[100]) * int(irn[1000]) * int(irn[10000]) * int(irn[100000]) * int(irn[1000000])
print number

Answer 1

Backticks are a deprecated alias for the repr() builtin function, so the second line is equivalent to the following:

irn = ''.join([repr(num) for num in range(loop_count)])

This uses a list comprehension to create a list of strings representing numbers, and then uses ''.join() to combine that list of strings into a single string, so this is equivalent to the following:

irn = ''
for num in range(loop_count):
    irn += repr(num)

Note that I used repr() here to be consistent with the backticks, but you will usually see str(num) to get the string representation of an int (they happen to be equivalent).