Python陷入无限While循环?

您的if和elif语句需要缩进。

while Query == 'Y':    
    Subject = input("Enter the Subject: \n> ")
    CatalogNbr= input("Enter the CatalogNbr: \n> ")
    if Subject == 'LIBS' and CatalogNbr == '150':
        print(f"The title of {Subject,CatalogNbr} is Introduction to Research")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'SDEV' and CatalogNbr == '400':
        print(f"The title of {Subject,CatalogNbr} is Secure Programming in the Cloud")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'PHIL' and CatalogNbr == '348':
        print(f"The title of {Subject,CatalogNbr} is Religions of the East")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'BEHS' and CatalogNbr == '320':
        print(f"The title of {Subject,CatalogNbr} is Disability Studies")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'PSYC' and CatalogNbr == '354':
        print(f"The title of {Subject,CatalogNbr} is Cross-Cultural Psychology")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")
    elif Subject == 'SPCH' and CatalogNbr == '482':
        print(f"The title of {Subject,CatalogNbr} is Intercultural Communication")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'WMST' and CatalogNbr == '200':
        print(f"The title of {Subject,CatalogNbr} is Introduction to Womens Studies Women and Society")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'HYST' and CatalogNbr == '482':
        print(f"The title of {Subject,CatalogNbr}is History of Japan to 1800")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'ASDT' and CatalogNbr == '370':
        print(f"The title of {Subject,CatalogNbr} is Interpreting Contemporary China")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'JAPN' and CatalogNbr == '333':
        print(f"The title of {Subject,CatalogNbr} is DJapanese Society and Culture")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")
    else:
        print(f"I'm sorry {Subject,CatalogNbr} is not an avalible option.")

    if Query == 'N':
        print("Thank you for using the Catalog Search!")```

你的程序应该是这样的。使用python时需要注意缩进。

Query = 'Y'

while Query == 'Y':
    Subject = input("Enter the Subject: \n> ")
    CatalogNbr = input("Enter the CatalogNbr: \n> ")
    if Subject == 'LIBS' and CatalogNbr == '150':
        print(f"The title of {Subject, CatalogNbr} is Introduction to Research")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'SDEV' and CatalogNbr == '400':
        print(f"The title of {Subject, CatalogNbr} is Secure Programming in the Cloud")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'PHIL' and CatalogNbr == '348':
        print(f"The title of {Subject, CatalogNbr} is Religions of the East")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'BEHS' and CatalogNbr == '320':
        print(f"The title of {Subject, CatalogNbr} is Disability Studies")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'PSYC' and CatalogNbr == '354':
        print(f"The title of {Subject, CatalogNbr} is Cross-Cultural Psychology")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'SPCH' and CatalogNbr == '482':
        print(f"The title of {Subject, CatalogNbr} is Intercultural Communication")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'WMST' and CatalogNbr == '200':
        print(f"The title of {Subject, CatalogNbr} is Introduction to Womens Studies Women and Society")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'HYST' and CatalogNbr == '482':
        print(f"The title of {Subject, CatalogNbr}is History of Japan to 1800")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'ASDT' and CatalogNbr == '370':
        print(f"The title of {Subject, CatalogNbr} is Interpreting Contemporary China")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")

    elif Subject == 'JAPN' and CatalogNbr == '333':
        print(f"The title of {Subject, CatalogNbr} is DJapanese Society and Culture")
        Query = input("\nWould you like to search for another title? (Y or N)\n> ")
    else:
        print(f"I'm sorry {Subject, CatalogNbr} is not an avalible option.")

if Query == 'N':
    print("Thank you for using the Catalog Search!")

因为python关心缩进,所以 while 循环只循环前两行,因为程序的其余部分被认为应该在while循环完成后执行。从第一个缩进所有代码 if