merge lists in runtime according to user inputs

Question

I have 4 lists like

list1 = []
list2 = []
list3 = []
list4 = []

then i need get user input and merge two lists at run time and print them ..

I have tried like this

first = input('enter 1st list')
second = input('enter 2nd list ')
if (first == 1):
    first  = list1
elif(first ==2):
    second = list2
....
....

but this is very long procedure and not appropriate for taking many inputs .

So please suggest me a better method..

Can you explain this better? What do you mean by merge? Do you want them sorted? As tuples? Alternating? — stephenfin, Nov 18 '13 at 08:42
Can you please tell us what you exactly trying to do. are the number of lists constant?. is there anyway to keep all the lists in a list? — Sravan K Ghantasala, Nov 18 '13 at 08:44
Don't write `if (…):`, just write `if …:`. The parentheses are redundant. — Marcelo Cantos, Nov 18 '13 at 08:44

score 2 · Answer 1 · answered Nov 18 '13 at 08:42

2

Put your 4 lists in another list:

lists = [list1, list2, list3, list4]

Now you can address them with indexing:

firstlist = lists[int(first) - 1]

answered Nov 18 '13 at 08:42

Martijn Pieters

i got it friends .. first = eval(input('enter 1st list')) second = eval(input('enter 2nd list ')) Any how thanks for support .... – kasinavijay Nov 18 '13 at 08:52
1

I'd not use `eval()`; `int()` will do fine here. – Martijn Pieters Nov 18 '13 at 09:48

score 0 · Answer 2 · answered Nov 18 '13 at 08:46

0

try this using dict

lists = {1: list1, 2: list2, 3:list3, 4:list4}

firstlist = lists[int(first)]

answered Nov 18 '13 at 08:46

Syed Habib M

score 0 · Accepted Answer · edited Dec 02 '13 at 12:44

0

Just use eval() method in python3.x if you are using python 2.x use raw_input .

edited Dec 02 '13 at 12:44

user987339

answered Dec 02 '13 at 12:14

Vijay Kasina

This is *not* the most sound advice. There is no need to use `eval()` when better and more secure options exist. – Martijn Pieters Dec 02 '13 at 12:21
Using `eval()` is not recommended especially when there is a better way, you can read more about it [here](http://stackoverflow.com/q/1832940/1982962) – Kobi K Dec 02 '13 at 13:16

3 Answers3