Python的附加方法不能正常工作

-4

def sem1Sort1(semester1, selectionSEM1): 

    list = [] 

    for period in semester1: 
     if period == 1: 
      for index in semester1[period]: 
       if index in selectionSEM1: 
        list.append(index) 

    return list 

def sem1Sort2(semester1, selectionSEM1): 

    list = [] 

    for period in semester1: 
     if semester1 == 2: 
      for index in semester1[period]: 
       if index in selectionSEM1: 
        list.append(index) 

    return list 

def main(): 

    selectionSEM1 = ["a", "b", "c", "d", "e", "f", "g", "h"] 
    selectionSEM2 = [] 

    semester1 = { 

    1: ["e", "f", "g", "h"], 2: ["a", "b", "c", "d"] , 

    } 

    SEM1period1 = sem1Sort1(semester1, selectionSEM1) 
    SEM1period2 = sem1Sort2(semester1, selectionSEM1) 

    print SEM1period1 
    print SEM1period2 

main()

當運行此代碼它打印出SEM1period1細，爲[「E」，「F」，「G」，「H」]，但是第二方法sem1Sort2，似乎不保存任何東西放入SEM1period2 - print語句打印出[]Python的附加方法不能正常工作

UPDATE：

def sem1Sort1(semester1, selectionSEM1): 

    list = [] 

    for period in semester1: 
     if period == 1: 
      for index in semester1[period]: 
       if index in selectionSEM1: 
        list.append(index) 

    return list 

def sem1Sort2(semester1, selectionSEM1): 

    list = [] 

    for period in semester1: 
     if period == 2: 
      for index in semester1[period]: 
       if index in selectionSEM1: 
        list.append(index) 

    return list 

def sem1Sort3(semester1, selectionSEM1): 

    list = [] 

    for period in semester1: 
     if period == 3: 
      for index in semester1[period]: 
       if index in selectionSEM1: 
        list.append(index) 

def main(): 

    selectionSEM1 = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l"] 
    selectionSEM2 = [] 


    semester1 = { 
    1: ["e", "f", "g", "h"], 2: ["a", "b", "c", "d"] , 
    3: ["i", "j", "k", "l"] 
    } 

    SEM1period1 = sem1Sort1(semester1, selectionSEM1) 
    SEM1period2 = sem1Sort2(semester1, selectionSEM1) 
    SEM1period3 = sem1Sort3(semester1, selectionSEM1) 

    print SEM1period1 
    print SEM1period2 
    print SEM1period3 

main()

爲什麼打印SEM1period3返回沒有？

來源

2014-04-28 LucasGrillos

修正雛鳥指出的錯誤後，函數'sem1Sort1'和'sem1Sort2'將完全相同，那麼爲什麼兩個不同的函數呢？而且，'list'在python中是一個_type_，所以創建一個名爲'list'的變量並不那麼明智。 – 0605002

夥計們，你不需要投票給我......我只是一個尋找答案的新手。抱歉。 – LucasGrillos

回答後請不要添加更多問題。 – 0605002

這裏您比較semester1整數但semester1是dict對象sem1Sort2功能，

for period in semester1: 
     if semester1 == 2:

其實你有與dict這樣的鍵比較整數，

for period in semester1: 
     if period == 2:

而且你休息的將是這樣的，

def sem1Sort1(semester1, selectionSEM1): 

    list = [] 

    for period in semester1: 
     if period == 1: 
      for index in semester1[period]: 
       if index in selectionSEM1: 
        list.append(index) 

    return list 

def sem1Sort2(semester1, selectionSEM1): 

    list = [] 

    for period in semester1: 
     if period == 2: 
      for index in semester1[period]: 
       if index in selectionSEM1: 
        list.append(index) 

    return list 

def main(): 

    selectionSEM1 = ["a", "b", "c", "d", "e", "f", "g", "h"] 
    selectionSEM2 = [] 

    semester1 = { 

    1: ["e", "f", "g", "h"], 2: ["a", "b", "c", "d"] , 

    } 

    SEM1period1 = sem1Sort1(semester1, selectionSEM1) 
    SEM1period2 = sem1Sort2(semester1, selectionSEM1) 

    print SEM1period1 
    print SEM1period2 

main()

輸出：

['e', 'f', 'g', 'h'] 
['a', 'b', 'c', 'd']

來源

2014-04-28 05:35:15 fledgling

現在既不返回任何東西......？ – LucasGrillos

對不起，我是一個新手，你必須給我更多的方向，對不起。 – LucasGrillos

@LucasGrillos請參閱更新的答案。 – fledgling

def sem1Sort1(semester1, selectionSEM1): 
list = [] 
for period in semester1: 
    if period == 1: 
    for index in semester1[period]: 
     if index in selectionSEM1: 
      list.append(index) 

return list 

def sem1Sort2(semester1, selectionSEM1): 
list = [] 
for period in semester1: 
    if period == 2: 
    for index in semester1[period]: 
    if index in selectionSEM1: 
     list.append(index) 
return list 

def main(): 
selectionSEM1 = ["a", "b", "c", "d", "e", "f", "g", "h"] 
selectionSEM2 = [] 
semester1 = { 
1: ["e", "f", "g", "h"], 2: ["a", "b", "c", "d"] , 
} 
SEM1period1 = sem1Sort1(semester1, selectionSEM1) 
SEM1period2 = sem1Sort2(semester1, selectionSEM1) 
print SEM1period1 
print SEM1period2 
main()

來源

2014-04-28 05:51:33 karnaf

你寫的像（如果學期== 2：）這需要總字典值，所以我們要提及特定的鍵值 – karnaf

爲了使這是一個很好的答案，你可以指出它們之間的差異和詳細說明。 – glglgl

爲什麼這麼複雜？

你不需要遍歷所有的字典條目，並挑選出匹配的條目 - 這使得字典的用法無意義。

相反，你可以告訴字典給你與給定鍵相關聯的值。您可以在main()功能這樣做，減少了功能

def semSort(semester, selection): 
    list = [] 
    for index in semester: 
     if index in selection: 
      list.append(index) 
    return list

，你可以在main()函數中調用諸如

def main(): 
    selectionSEM1 = ["a", "b", "c", "d", "e", "f", "g", "h"] 
    selectionSEM2 = [] 
    semester1 = { 
     1: ["e", "f", "g", "h"], 2: ["a", "b", "c", "d"] , 
    } 

    SEM1period1 = semSort(semester1[1], selectionSEM1) 
    SEM1period2 = semSort(semester1[2], selectionSEM1) 

    print SEM1period1 
    print SEM1period2 

main()

，你會實現你想要的。

你甚至可以細化它：

def semSort(semester, selection): 

    result = [] 
    sel_set = set(selection)  
    for index in semester: 
     if index in sel_set: 
      result.append(index) 

    return result

設定使得查找更快。

def semSort(semester, selection): 
    sel_set = set(selection) 
    return [index for index in semester if index in sel_set]

更加緊湊。

來源

2014-04-28 05:58:38 glglgl

Python的附加方法不能正常工作

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