**SPIP**
# Article proposé
L’article "**Two simple iterators : lists and enumerations**
(https://www.spip.net/ecrire/?exec=article&id_article=6487)" est proposé
à la publication depuis le dimanche 20 janvier 2019.
* * *
## Two simple iterators : lists and enumerations
dimanche 20 janvier 2019 , par
[Loiseau2nuit](.././?page=auteur&id_auteur=5162&)
Among the numerous powerful iterators that come with SPIP 3, two of them
are shinning from their simplicity : lists and enumerations.
## List Iterator
The list iterator lets you loop on list items. Items can be words, figures
or, tiny bits of text. It’s called by `DATA` loop’s `liste` criteria,
to which we transmit the items list that should be looped on :
This loop displays a list of the first prime numbers :
<ul>
<BOUCLE_prime_num
(DATA)
{liste 2, 3, 5, 7, 11, 13}
>
<li>
#VALEUR
</li>
</BOUCLE_prime_num>
</ul>
It possible to use every criterias that apply to all loops
(https://www.spip.net/ecrire/?exec=article&id_article=2085).
**Specify separator :**
<BOUCLE_months
(DATA)
{liste january, february, march, april}
{" ; "}
>
#VALEUR
(
[
(
#VALEUR
|couper
{3}
)
]
)
</BOUCLE_months>
will return : january (jan) ; february (feb) ; march (mar) ; april (apr)
**Reverse the reading loop order :**
<BOUCLE_months
(DATA)
{liste 1, 10, 100, 1000}
{", "}
{inverse
#ENV
{reverse}
}
>
#VALEUR
</BOUCLE_months>
will return : "1, 10, 100, 100, 1000" or "1000, 100, 10, 1" depending on
’reverse’ value in the environment.
**Loop only on a list’s sub-dataset :**
<BOUCLE_months
(DATA)
{liste january, february, march, april, may, june, july}
{", "}
{3,2}
>
#VALEUR
</BOUCLE_months>
will jump 3 months forward and return only 2 : "april, may"
**Values for markers can be calculated :**
<BOUCLE_colors
(DATA)
{liste
#GET
{mostlikedcolor}
,
#ENV
{chosencolor}
}
{", "}
>
#VALEUR
</BOUCLE_colors>
## Enumeration iterator
Enumeration iterator is a realy simple loop. It’s most generic use is, as
following
<BOUCLE_enumerate
(DATA)
{enum val1, val2}
>
#VALEUR
</BOUCLE_enumerate>
or
<BOUCLE_enumerate
(DATA)
{enum val1, val2, interval}
>
#VALEUR
</BOUCLE_enumerate>
`val1` and `val2` are two numeric values or, 2 characters. SPIP finding out
which one, of the 2 values, is the smallest, this loop is going to
enumerate values between `val1` and `val2`. In the first variant, no
`interval` is set : it’s worth 1 by default.
**Integers, no "1" :**
1. <BOUCLE\_enum (DATA) {enum 10,15} {", "} > #VALEUR </BOUCLE\_enum>
is looping on values, starting 10, breaking on 15, thus returning "10, 11,
12, 13, 14, 15".
**Decimals, no "1" :**
1. <BOUCLE\_enum (DATA) {enum 15.5,10.3} {", "} > #VALEUR </BOUCLE\_enum>
is looping on values, starting 15, breaking on 10, thus returning "15.5,
14.5, 13.5, 12.5, 11.5, 10.5".
**Integers, no "2" :**
1. <BOUCLE\_enum (DATA) {enum 10, 15, 2} {", "} > #VALEUR </BOUCLE\_enum>
is looping on values from 10 to 15, with an `interval` of 2, thus returning
"10, 12, 14".
**Letters :**
1. <BOUCLE\_enum (DATA) {enum g,m} {", "} > #VALEUR </BOUCLE\_enum>
is looping on letters from "g" to "m", thus returning "g, h, i, j, k, l,
m".
— Envoyé par SPIP (https://www.spip.net/)
