All integers that can be represented by floating point numbers have an exact representation. So you can safely use int on the result. Inexact representations occur only if you are trying to represent a rational number with a denominator that is not a power of two. That this works is not trivial at all! It’s a property … Read more
It presents a prompt to the user (the optional arg of raw_input([arg])), gets input from the user and returns the data input by the user in a string. See the docs for raw_input(). Example: This differs from input() in that the latter tries to interpret the input given by the user; it is usually best to avoid input() and to stick with raw_input() and custom … Read more
You’re using Python 2.x, where integer divisions will truncate instead of becoming a floating point number. You should make one of them a float: or from __future__ import division, which the forces / to adopt Python 3.x’s behavior that always returns a float.
In Python 2.x: range creates a list, so if you do range(1, 10000000) it creates a list in memory with 9999999 elements. xrange is a sequence object that evaluates lazily. In Python 3: range does the equivalent of Python 2’s xrange. To get the list, you have to explicitly use list(range(…)). xrange no longer exists.
On Linux at least, there’s no difference as far as I can tell. Here’s a test script and its corresponding OS syscalls (using strace); tested on python 2.7.9. See http://man7.org/linux/man-pages/man2/open.2.html for more details on the file access and creation flags. It’s not accurate to say a file object opened with ‘r+’ cannot be used to truncate a file – … Read more