[英]Programming resorting to Else statement when If is True
我正在處理詞典列表:
student_list = [{'id': 12341, 'first_name': 'Alice', 'last_name': 'Anderson',
'assignments': [('assignment_1', 0), ('assignment_2', 2), ('assignment_3', 4)]},
{'id': 12342, 'first_name': 'Boris', 'last_name': 'Bank',
'assignments': [('assignment_1', 1), ('assignment_2', 3), ('assignment_3', 0)]},
{'id': 12343, 'first_name': 'Carl', 'last_name': 'Cape',
'assignments': [('assignment_1', 2), ('assignment_2', 4), ('assignment_3', 1)]},
{'id': 12344, 'first_name': 'Didi', 'last_name': 'Dawson',
'assignments': [('assignment_1', 3), ('assignment_2', 0), ('assignment_3', 2)]},
{'id': 12345, 'first_name': 'Ed', 'last_name': 'Enders',
'assignments': [('assignment_1', 4), ('assignment_2', 1), ('assignment_3', 3)]}]
我需要編寫一個按學生姓名搜索字典的函數,以查看是否有匹配的作業名稱和年級。 如果存在,則返回True,否則返回False,並將其添加到列表中。 我已經掌握了什么,但是無論我鍵入的是true還是false,如果參數讀取為false並將賦值添加為元組,則無論如何。
您能幫我找到此功能所需的缺少說明嗎?
def add_grade(student, assignment_name, grade):
for s in student_list:
if s['first_name'] == student:
if any(s['assignments']) == (assignment_name, grade):
print(True)
else:
s['assignments'].append((assignment_name, grade))
print(False)
add_grade('Carl', 'assignment_2', 2)
print(student_list)
編輯:第一個答案幫助我使代碼正常工作(謝謝!)
現在,我將其放寬並使其變得更松散,這樣就不必將作業添加兩次並添加兩個不同的等級,而是將其放置為已經存在。 我制作的東西笨拙且雜亂,似乎修復起來很容易,但我不知道。 思考?
def add_grade2(student, assignment_name, grade):
for s in student_list:
if s['first_name'] == student:
if (assignment_name, grade) in s['assignments']:
print(True)
elif (assignment_name, 0) in s['assignments']:
print('That assignment has a different grade. ')
break
elif (assignment_name, 1) in s['assignments']:
print('That assignment has a different grade. ')
break
elif (assignment_name, 2) in s['assignments']:
print('That assignment has a different grade. ')
break
elif (assignment_name, 3) in s['assignments']:
print('That assignment has a different grade. ')
break
elif (assignment_name, 4) in s['assignments']:
print('That assignment has a different grade. ')
break
else:
s['assignments'].append((assignment_name, grade))
print(False)
add_grade2('Alice', 'assignment_1', 3)
print(student_list)
問題是,對於一個學生, "assignments"
是一個元組列表,在第一種情況下,您將整個列表與一個元組進行比較,在第二種情況下,您只需檢查是否assignment_name
(第一個元組的位置)在列表中。
您可以將作業存在檢查更改為:
if (assignment_name, grade) in s['assignments']:
print(True)
else:
s['assignments'].append((assignment_name, grade))
print(False)
另外,為了限制縮進並使內容更易於閱讀,您可以使用next
查找正確的學生詞典。 然后您將擁有:
def add_grade(student, assignment_name, grade):
s = next(s for s in student_list if s['first_name'] == student)
if (assignment_name, grade) in s['assignments']:
print(True)
else:
s['assignments'].append((assignment_name, grade))
print(False)
編輯 :每個作業僅允許一個成績(不得覆蓋):
for i in range(len(s['assignments'])):
if s['assignments'][i][0] == assignment_name:
if s['assignments'][i][1] == grade:
print(True)
else:
print('That assignment has a different grade.')
return
s['assignments'].append((assignment_name, grade))
print(False)
或(邏輯更簡單,但計算量略多):
if (assignment_name, grade) in s['assignments']:
print(True)
elif any(a_name == assignment_name for a_name, _ in s['assignments']):
print('That assignment has a different grade.')
else:
s['assignments'].append((assignment_name, grade))
print(False)
覆蓋:
for i in range(len(s['assignments'])):
if s['assignments'][i][0] == assignment_name:
s['assignments'][i] = (assignment_name, grade)
print(True)
return
s['assignments'].append((assignment_name, grade))
print(False)
從any
返回的結果將為True
或False
。 那將永遠不會等於(assignment_name, grade)
。
尚不清楚您是否只希望匹配名稱或名稱和等級。 無論哪種方式,您都將需要一個循環來搜索可能性。
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