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From: Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid>
Newsgroups: fr.comp.lang.python
Subject: Re: Somme, =?utf-8?Q?r=C3=A9cursive?=
Date: Fri, 30 Apr 2021 18:14:00 +0200
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Olivier Miakinen <om+news@miakinen.net> writes:

> Le 30/04/2021 17:06, je r=C3=A9pondais =C3=A0 Benoit Izac :
>>=20
>> Et vu la r=C3=A9ponse de raph14 c'est la somme.
>>=20
>> Noter que je ne peux pas lui r=C3=A9pondre parce que le =C2=AB PEAR::Net=
_NNTP v1.5.0
>> (stable) =C2=BB de Giganews met du 8-bits dans la champ Subject et que =
=C3=A7a fait
>> buguer mon SeaMonkey.
>
> En tout cas, si c'est bien la somme, et vu que je suis moi-m=C3=AAme d=C3=
=A9butant
> (un mois =C3=A0 peu pr=C3=A8s ?) je me permets de divulgacher la solution.
>
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> def somme(liste):
>     return sum(liste)
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

Ou simplement :

somme =3D sum

> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> def somme(liste):
>     if len(liste) =3D=3D 0:
>         return 0
>     return liste[0] + somme(liste[1:])
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

Pour =C3=A9viter la construction d'une nouvelle liste =C3=A0 chaque appel :

def somme (liste, i=3D0):
    if i < len (liste):
        return liste[i] + somme (liste, i+1)
    else:
        return 0

ou encore, pour faire le malin :

def somme (liste, i=3D0):
    return liste[i] + somme (liste, i+1) if i < len (liste) else 0

mais clairement, les listes de Python ne sont pas vraiment faites pour
l'algorithmique r=C3=A9cursive classique.

-- Alain.