I am currently going through the codecademy course learning python. I am not trying to solve a problem, just some info. My current problem is:

```
def square(n):
"""Returns the square of a number."""
squared = n ** 2
print "%d squared is %d." % (n, squared)
return squared
# Call the square function on line 10! Make sure to
# include the number 10 between the parentheses.
square(10)
```

My question is, on the print line, the “%” are followed by a “d”. In earlier problems i have seen them with “s” and even ": \ ". I am wondering if there is a site or document that can tell me what all these are used for and when im supposed to use each one.

Thanks