python成長之路:11/18,常用魔法總結
阿新 • • 發佈:2020-11-18
# 艹他媽的字典魔法----------------------------------------------- # info = {"k1": 1, "k2": 2, "k3": 4, (1, 2, 3,): [1, 2, 3, 4, {"k1": 1, "k2": [1, 2]}]} # print(info[(1, 2, 3,)][4]["k2"][1]) # dict # 1.fromkeys() 根據序列,來建立字典,並指導統一的值 # v = info.fromkeys(["k1",123,"k3"],123) # # print(v) # 2 字典根據key值索引取值 info["k1"]如果key值不尊重會報錯 # print(info["k1"]) # 3.get()根據key進行取值,如果key不純在顯示None,("k1",111)不存在 # "k1"則顯示111 # info = {"k1": 1, "k2": 2, "k3": 4, (1, 2, 3,): [1, 2, 3, 4, {"k1": 1, "k2": [1, 2]}]} # v = info.get("k1",11111) # print(v) # 4.pop():根據key值刪除,引數,如果key不存在顯示引數 # info = {"k1": 1, "k2": 2, "k3": 4, (1, 2, 3,): [1, 2, 3, 4, {"k1": 1, "k2": [1, 2]}]} # # v= info.pop('k1',99) # print(v,info) # 5.popitems() 不能傳引數,隨機刪除並獲取值 # info = {"k1": 1, "k2": 2, "k3": 4, (1, 2, 3,): [1, 2, 3, 4, {"k1": 1, "k2": [1, 2]}],"k6":(1)} # v = info.popitem() # print(v,info) # 6. setdefault("k3",123) :設定,檢視該字典裡是否有"k3",如果key裡面有則返回"k3"對應 # 的值,如果沒有則在字典裡設定一個"k3":123 # dic = {"k1":'v1', # "k2":'v2' # } # v=dic.setdefault("k3",123) # # print(dic,v) # 7.update()更新,根據key值更新value,如果key值不存在直接在該字典裡建立新的鍵值對 # dic = {"k1":'v1', # "k2":'v2' # } # dic.update({"k1":1111,"k2":2222,"k3":3333}) # dic.update({"k2":222}) # print(dic) # 字典魔法常用: key() , value() ,items() , update() , get() # dic = {"k1":'v1', # "k2":'v2' # } # v = dic.get("k1") # print(v) # 一、數字 # # int(..) # # test = "123" # # t = int(test) # # print(t) # # 二、字串 # # replace/find/jion/strip/startwith/split/upper/lower/format # # # test = "i am {name},i like {like}" # # test = test.format(name = input("請輸入名字") , like = input("請輸入一個女生的名字")) # # print(test) # # **表示可以加字典format # # test = "i am {name},i like {like}" # # v = test.format(**{"name":'alex',"like":'play girls'}) # # print(v) # # # 三、列表 # # append\extend\insert # # 索引,切片,迴圈 # # li = [1,2,3,"4",(5),[6],{"k7":7}] # # li.insert(len(li)-1,"2個大傻逼") # # print(li) # # li = [1,2,3,"4",(5),[6],{"k7":7}] # # for i in li : # # print(i) # # # 四、元組 # # 忽略 # # 一級元素不能修改,刪除 # # # 五、字典 # # get\update\keys\values\items # # for迴圈,索引 # # dic = { # # "k1":'v1' # # }-+ # # # v = 'v1' in dic.values() # # print(v) # # # 六、布林值 # # 0 1 # # bool(..) # # None "" {} [] () 0 --> False # # # v = 0 # # s = bool(v) # # print(s) #enumetare(dic,1):把一個可迭代物件,組合成一個索引序列輸出