Jorge Godoy <godoy at ieee.org> wrote: > "Riccardo Rossi" <riccardo.rorssi76 at email.it> writes: >> Hi all! >> >> How does Python pass arguments to a function? By value or by reference? > IIRC, by reference. It uses a copy on write algorithm. Copy-on-write is an optimization. It doesn't affect the semantics of the laguage.