4
votes

I was researching some information on the topic of trial division, and I came across this symbol in Python:

//=

I got this from here where the code in the example says:

n //= p

I can't tell what this is supposed to mean, and my research continues to bring poor results in terms of webpages.

3

3 Answers

10
votes

// is integer division and the

n //= p

syntax is short for

n = n // p

except the value n is modified directly if it supports this.

4
votes

When you see an operator followed by an =, that is performing the operation and then assigning it into the variable. For example, x += 2 means x = x + 2 or add 2 to x.

The // operator specifically does integer devision instead of floating point division. For example, 5 // 4 gives you 1, while 5 / 4 gives you 1.25 (in Python 3).

Therefore, x //= 3 means divide x by 3 (in an integer division fashion), and store the value back into x. It is equivalent to x = x // 3

1
votes

// is the floor division operator, therefore //= is simply the inplace floor division operator.