grouping a list in individual lists in a base list or completely individual in maya python

Question

i have a dynamic group: for example we have a list with 20 items in it in this time.... i wanna make this list in 4 individual list with 5 items something like this is in my head..

a = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
z = len(a)/4
b = []
for i in range(z)

and after i don't know what i should do.......

i did something like this but it's completely wrong:

for i in range(len(a)):
    for j in range(z):
        b.append(a)

this is my codes:

import maya.cmds as cm
import random as random
myList = cm.ls(sl = True)
random.shuffle(myList)
b = [myList[i:i+5] for i in range(0, len(myList), 5)]
for i in b:
    print str(i)+".v"

the result is:

[u'curve13', u'curve26', u'curve5', u'curve40', u'curve17'].v

but i need:

[u'curve13.v', u'curve26.v', u'curve5.v', u'curve40.v', u'curve17.v'].v

If you print `i` and `j` you can probably see why that's not working. And perhaps correct it. It might not be pythonic, but a good exercise nonetheless. — keyser, Aug 02 '13 at 18:28
_"i wanna make this list in 4 individual list with 5 items"_. Please be more specific. Which items go in which lists? Show us what output you expect. — Kevin, Aug 02 '13 at 18:32

falsetru · Accepted Answer · 2013-08-02T19:47:49.687

0

Use slice operation:

>>> a = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
>>> b = [a[i:i+5] for i in range(0, len(a), 5)]
>>> b
[[1, 2, 3, 4, 5], [6, 7, 8, 9, 10], [11, 12, 13, 14, 15], [16, 17, 18, 19, 20]]
>>> b[2][3]
14

UPDATE response to comment

access items

>>> for item in b[2]: print '{}.v'.format(item)
...
11.v
12.v
13.v
14.v
15.v

UPDATE2

>>> a = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
>>> n = len(a)
>>> b = [a[n*i/4:n*(i+1)/4] for i in range(4)]
>>> c, d, e, f = b
>>> c
[1, 2, 3, 4, 5]
>>> d
[6, 7, 8, 9, 10]
>>> e
[11, 12, 13, 14, 15]
>>> f
[16, 17, 18, 19, 20]

edited Aug 02 '13 at 19:47

answered Aug 02 '13 at 18:28

falsetru

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could you explain to me what does this part do? for i in range(0, len(a), 5) what does exactly (0,len(a),5) – Amin Khormaei Aug 02 '13 at 18:33
and how can i make that list like this: b = [1,2,3,4,5] , c = [6,7,8,9,10] and so forth – Amin Khormaei Aug 02 '13 at 18:35
@iran, In `range(0, 20, 5)`. `0` is start value, `20` is stop value (exlusive). `5` is step. `range(0, 20, 5)` yields `[0, 5, 10, 15]`. – falsetru Aug 02 '13 at 18:37
@iran, Why do you want to make separated variables instead of list of list? Normally such thing is not required. What do you want to really do? – falsetru Aug 02 '13 at 18:39
i can't access to items in list.i'm scripting in maya – Amin Khormaei Aug 02 '13 at 18:46
@iran, You can access items as `b[..][..]`. For example, `b[2][3]` yield 14. – falsetru Aug 02 '13 at 18:47
when i do this to my list: for i in b: print str(i)+".v" it does this: [1, 2, 3, 4, 5].v i wanna do this: [1.v,2.v,3.v,4.v,5.v] how can i have access to each item? – Amin Khormaei Aug 02 '13 at 18:50
@iran, I don't understand ... Do you want print all items? – falsetru Aug 02 '13 at 18:54
@iran, I added an example code that access third group(`[2]`) items. – falsetru Aug 02 '13 at 18:59
i'll add something in my question – Amin Khormaei Aug 02 '13 at 19:00
i always want to divide myList by 4 – Amin Khormaei Aug 02 '13 at 19:35
@iran, Hmm.. See **UPDATE2**. – falsetru Aug 02 '13 at 19:48

grouping a list in individual lists in a base list or completely individual in maya python

1 Answers1