最近在學習 python 語言。大致學習了 python 的基礎語法。覺得 python 在數據處理中的地位和它的 list 操作密不可分。
特學習了相關的基礎操作并在這里做下筆記。
'''Python --version Python 2.7.11Quote : https://docs.python.org/2/tutorial/datastructures.html#more-on-listsAdd by camel97 2017-04'''list.append(x) #在列表的末端添加一個新的元素Add an item to the end of the list; equivalent to a[len(a):] = [x].
list.extend(L)#將兩個 list 中的元素合并到一起
Extend the list by appending all the items in the given list; equivalent to a[len(a):] = L.
list.insert(i, x)#將元素插入到指定的位置(位置為索引為 i 的元素的前面一個)
Insert an item at a given position. The first argument is the index of the element before which to insert, so a.insert(0, x) inserts at the front of the list, and a.insert(len(a), x) is equivalent to a.append(x).
list.remove(x)#刪除 list 中第一個值為 x 的元素(即如果 list 中有兩個 x , 只會刪除第一個 x )
Remove the first item from the list whose value is x. It is an error if there is no such item.
list.pop([i])#刪除 list 中的第 i 個元素并且返回這個元素。如果不給參數 i ,將默認刪除 list 中最后一個元素
Remove the item at the given position in the list, and return it. If no index is specified, a.pop() removes and returns the last item in the list. (The square brackets around the i in the method signature denote that the parameter is optional, not that you should type square brackets at that position. You will see this notation frequently in the Python Library Reference.)
list.index(x)#返回 list 中 , 值為 X 的元素的索引
Return the index in the list of the first item whose value is x. It is an error if there is no such item.
list.count(x)#返回 list 中 , 值為 x 的元素的個數
Return the number of times x appears in the list.
demo:
#-*-coding:utf-8-*-L = [1,2,3] #創建 list L2 = [4,5,6]print LL.append(6) #添加print LL.extend(L2) #合并print LL.insert(0,0) #插入print LL.remove(6) #刪除print LL.pop() #刪除print Lprint L.index(2)#索引print L.count(2)#計數L.reverse() #倒序print L
result:
[1, 2, 3][1, 2, 3, 6][1, 2, 3, 6, 4, 5, 6][0, 1, 2, 3, 6, 4, 5, 6][0, 1, 2, 3, 4, 5, 6][0, 1, 2, 3, 4, 5]21[5, 4, 3, 2, 1, 0]
list.sort(cmp=None, key=None, reverse=False)
Sort the items of the list in place (the arguments can be used for sort customization, see sorted() for their explanation).
1.對一個 list 進行排序。默認按照從小到大的順序排序
L = [2,5,3,7,1]L.sort()print L==>[1, 2, 3, 5, 7]L = ['a','j','g','b']L.sort()print L==>['a', 'b', 'g', 'j']
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