Python | Create two lists with first half and second half elements of a list

Program:

# define a list 
list = [10, 20, 30, 40, 50, 60]

# Create list1 with half elements (first 3 elements)
list1 = list [:3]
# Create list2 with next half elements (next 3 elements)
list2 = list [3:]

# print list (s)
print "list : ",list
print "list1: ",list1
print "list2: ",list2

Output

    list :  [10, 20, 30, 40, 50, 60]
    list1:  [10, 20, 30]
    list2:  [40, 50, 60]

Using list[0:3] and list[3:6] instaed of list[:3] and list[3:]

We can also use list[0:3] instead of list[:3] to get first 3 elements and list[3:6] instead of list[3:] to get next 3 elements after first 3 elements.

Consider the program:

# define a list 
list = [10, 20, 30, 40, 50, 60]

# Create list1 with half elements (first 3 elements)
list1 = list [0:3]
# Create list2 with next half elements (next 3 elements)
list2 = list [3:6]

# print list (s)
print "list : ",list
print "list1: ",list1
print "list2: ",list2

Output

    list :  [10, 20, 30, 40, 50, 60]
    list1:  [10, 20, 30]
    list2:  [40, 50, 60]

By considering length of the list

Let suppose list has n elements, then we can use list[0:n/2] and list[n/2:n].

Consider the program:

If there are ODD numbers of elements in the list, program will display message "List has ODD number of elements." And exit.

# define a list 
list = [10, 20, 30, 40, 50, 60]

# get the length of the list 
n = len(list)

# condition to check length is EVEN or not
# if lenght is ODD, show message and exit
if( n%2 != 0 ):
    print "List has ODD number of elements."
    exit()
    
# Create list1 with half elements (first 3 elements)
list1 = list [0:n/2]
# Create list2 with next half elements (next 3 elements)
list2 = list [n/2:n]

# print list (s)
print "list : ",list
print "list1: ",list1
print "list2: ",list2

Output

    list :  [10, 20, 30, 40, 50, 60]
    list1:  [10, 20, 30]
    list2:  [40, 50, 60]