我正在尝试添加一个 if 语句来检查无效输入。如果用户输入"is",它会像它应该的那样工作并再次循环,如果用户输入“否”则结束。但出于某种奇怪的原因,无论答案是什么:是、否、随机字符等。它总是打印“无效输入”语句。我试图只在答案不是"is"或“否”时打印。
while cont == "Yes":
word=input("Please enter the word you would like to scan for. ") #Asks for word
capitalized= word.capitalize()
lowercase= word.lower()
accumulator = 0
print ("\n")
print ("\n") #making it pretty
print ("Searching...")
fileScan= open(fileName, 'r') #Opens file
for line in fileScan.read().split(): #reads a line of the file and stores
line=line.rstrip("\n")
if line == capitalized or line == lowercase:
accumulator += 1
fileScan.close
print ("The word", word, "is in the file", accumulator, "times.")
cont = input ('Type "Yes" to check for another word or \
"No" to quit. ') #deciding next step
cont = cont.capitalize()
if cont != "No" or cont != "Yes":
print ("Invalid input!")
print ("Thanks for using How Many!") #ending
最佳答案
那是因为无论您输入什么,至少一个的测试为真:
>>> cont = 'No'
>>> cont != "No" or cont != "Yes"
True
>>> (cont != "No", cont != "Yes")
(False, True)
>>> cont = 'Yes'
>>> cont != "No" or cont != "Yes"
True
>>> (cont != "No", cont != "Yes")
(True, False)
改用和
:
>>> cont != 'No' and cont != 'Yes'
False
>>> cont = 'Foo'
>>> cont != 'No' and cont != 'Yes'
True
或使用成员资格测试(in
):
>>> cont not in {'Yes', 'No'} # test against a set of possible values
True
关于python - If 语句始终打印 (Python),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/17661206/