python - if 语句和多个条件出错

Question

我在检查输入是否正确的 if 语句中遇到问题。当我输入M或F时，它会打印出“错误输入”，我不太明白。

def check(aw,iw):
    if abs(aw-iw)<5 :
        print "Your weight is normal."
    elif abs(aw-iw)>5 and abs(aw-iw)<15 :
        print "Your weight is about normal."
    else:
        print "Your weight is not normal."
    return

print "Enter your gender (M/F)"
gender=raw_input()
if gender!='M' or gender!='F':
    print "Wrong input."
else:
    if gender=='M':
        w=raw_input("Enter your weight (kg) :")
        h=raw_input("Enter your height (cm) :")
        idw=110-h
        check(w,idw)
    else:
        w = raw_input("Enter your weight (kg) :")
        h = raw_input("Enter your height (cm) :")
        idw = 110 - h
        check(w, idw)

Answer 1

每个输入要么不等于M，要么不等于F(例如，M不等于F)。相反，您需要检查您的输入是否不等于 M 且 不等于 F:

if gender != 'M' and gender != 'F':
    # Here ------^
    print "Wrong input."

或者，更优雅地使用 not in 运算符:

if gender not in ('M', 'F'):
    print "Wrong input."