列表list的增刪改查
阿新 • • 發佈:2018-12-11
# _author:VULCAN # date:2018/8/14 a = ["張三", "李四", "王五", "馬六", "王五", "李七"] # 對列表的查詢操作(切片): # print(a[0]) # print(a[0:])#依次列印到最後等同於 print(a[0::1]) # print(a[1::2])#從左到右每隔一個去取值 2是步長 # print(a[3::-3])#從右到左每擱兩個去取值 # print(a[-3::2])#從左到右每擱一個去取值 # print(a[-3::-2])#從右到左每隔一個去取值 # print(a[1:-1:-1])#結果為空值 # print("李四" in a) # print("李四" not in a) # 新增操作:append insert # a.append('周八')#預設新增在做後面,追加 # print(a) # a.insert(2, '黎明') # print(a)#新增值時需要索引值 # 修改操作: # a[0] = "王麻子"#直接根據下標修改值 a[index] = 新的值 # print(a) # a[1: 3] = ["第三方", "安撫"]#根據索引範圍來修改值 a[start:end] = [a,b,c] # print(a) # 刪除操作:remove pop del # a.remove(a[2]) # a.remove("李七")#直接刪除某一個值 # print(a) #清空列表 # a.clear() # print(a) # a.pop(2) # print(a)#根據下標刪除 # del a[1:3]#連續刪除某些值 # del a[0::2]#del可以新增切片 # print(a) # del()可以刪除整個列表 # del a # print(a) # count():計算元素在列表中的個數 # l = [1, 1, 11, 1, 33, 45, 46, 46, 46813, 1345, 54, 64, 64, 46, 43, 891].count(1) # m = ["999", "999", "999", "666", "666", "888", "777", "555", "333"].count("999") # print(l) # print(m) # extend():把後邊的資料新增到前邊的資料中,對資料進行擴充套件 # a = [1, 2, 3, 4] # b = [7, 8, 9, 10] # a.extend(b) # print(a) # print(b) # index():根據元素名字查詢元素的下標位置 # print(a.index("張三")) # reverse():對元素進行倒序排列,沒有返回值 # a.reverse() # print(a) # sort方法,對一組資料進行排序,從小到大 # b = [543, 2657, 5, 2345, 57, 67, 5, 345, 245, 4, 54] # b.sort() # print(b) # b.sort(reverse=True)#reverse=True預設是true,設為false後就是將資料先從小到大排序,再把得到的資料從新從大到小排序 # print(b) #sorted()效果等同於sort() # x = sorted(b) # print(x) # name0='wuchao' # name1='jinxin' # name2='xiaohu' # name3='sanpang' # name4='ligang' # # names='wuchao jinxing xiaohu sanpang ligang' # a=['wuchao','jinxin','xiaohu','sanpang','ligang',['wuchao','jinxin']] # 增刪改查 # 查 切片 [] # print(a[1:])#取到最後 # print(a[1:-1])#取到倒數第二值 # print(a[1:-1:1])#從左到右一個一個去取 # print(a[1::2])#從左到右隔一個去取 # print(a[3::-1]) # b=a[3::-1] # print(b)#['sanpang', 'xiaohu', 'jinxin', 'wuchao'] # print(a[-2::-1]) # print(a[1:-1:-2]) # 新增 append insert # a.append('xuepeng') #預設插到最後一個位置 # print(a) # a.insert(1,'xuepeng') #將資料插入到任意一個位置 # print(a) # 修改 # # a[1]='haidilao' # print(a) # a[1:3]=['a','b'] # print(a) # 刪除 remove pop del # a.remove(a[0]) # print(a) # b=a.pop(1) # print(a) # print(b) # # del a[0] # print(a) # del a # print(a) # a.remove(['wuchao','jinxin']) # print(a) # count:計算某元素出現次數 # t=['to', 'be', 'or', 'not', 'to', 'be'].count('to') # print(t) # extend # a = [1, 2, 3] # b = [4, 5, 6] # a.extend(b) # print(a) # print(b) # index # 根據內容找位置 # a = ['wuchao', 'jinxin', 'xiaohu','ligang', 'sanpang', 'ligang', ['wuchao', 'jinxin']] # # # first_lg_index = a.index("ligang") # print("first_lg_index",first_lg_index) # little_list = a[first_lg_index+1:] # # second_lg_index = little_list.index("ligang") # print("second_lg_index",second_lg_index) # # second_lg_index_in_big_list = first_lg_index + second_lg_index +1 # # print("second_lg_index_in_big_list",second_lg_index_in_big_list) # print("second lg:",a[second_lg_index_in_big_list]) # reverse # a = ['wuchao', 'jinxin', 'xiaohu','ligang', 'sanpang', 'ligang'] # a.reverse() # print(a) # x = [4, 6, 2, 1, 7, 9] # x.sort(reverse=True) # print(x)#[1, 2, 4, 6, 7, 9] a = ['wuchao', 'jinxin', 'Xiaohu', 'Ligang', 'sanpang', 'ligang'] # a.sort() # print(a) print(a.count("haidilao ge")) print(a.pop()) print(a)