Given a list, and we have to create two lists from first half elements and second half elements of a list in Python.
给定一个列表，我们必须在Python中从列表的前一半元素和后一半元素创建两个列表。
Example:
例：
Input:
list: [10, 20, 30, 40, 50, 60]
Output:
list1: [10, 20, 30]
list2: [40, 50, 60]
Logic:
逻辑：
First take list (Here, we are taking list with 6 elements).
第一个清单(此处，我们列出了包含6个元素的清单)。
To get the elements from/till specified index, use list[n1:n2] notation.
要从/直到指定索引获取元素，请使用list [n1：n2]表示法。
To get first half elements, we are using list[:3], it will return first 3 elements of the list.
为了获得前半个元素，我们使用list [：3] ，它将返回列表的前三个元素。
And, to get second half elements, we are using list[3:], it will return elements after first 3 elements. In this example, we have only 6 elements, so next 3 elements will be returned.
并且，要获取后半个元素，我们使用list [3：] ，它将在前三个元素之后返回元素。 在此示例中，我们只有6个元素，因此将返回下3个元素。
Finally, print the lists.
最后，打印列表。
Program:
程序：
# 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
输出量
list : [10, 20, 30, 40, 50, 60]
list1: [10, 20, 30]
list2: [40, 50, 60]
使用列表[：3]和列表[3：]的列表[0：3]和列表[3：6] (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.
我们还可以使用list [0：3]代替list [：3]获得前3个元素，并使用list [3：6]代替list [3：]获得前3个元素之后的下3个元素。
Consider the program:
考虑该程序：
# 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
输出量
list : [10, 20, 30, 40, 50, 60]
list1: [10, 20, 30]
list2: [40, 50, 60]
通过考虑清单的长度 (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].
假设list有n个元素，那么我们可以使用list [0：n / 2]和list [n / 2：n] 。
Consider the program:
考虑该程序：
If there are ODD numbers of elements in the list, program will display message "List has ODD number of elements." And exit.
如果列表中包含奇数个元素，程序将显示消息“列表中包含奇数个元素”。 然后退出。
# 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
输出量
list : [10, 20, 30, 40, 50, 60]
list1: [10, 20, 30]
list2: [40, 50, 60]