python中if条件分支

1、条件成立执行

>>> a = 50
>>> if a > 10:
    print("xxx")

    
xxx
>>> if a < 10:
    print("yyy")

    
>>> if a == 50:
    print("zzz")

    
zzz

score = int(input("score="))
if 100 >= score >= 90:
    print("AAA")
if 90 > score >= 80:
    print("BBB")
if 80 > score >= 60:
    print("CCC")
if 60 > score >= 0:
    print("DDD")
if score > 100 or score <= 0:
    print("error! range: 0-100")

score = int(input("score="))
if 100 >= score >=90:
    print("AAA")
else:
    if 90 > score >= 80:
       print("BBB")
    else:
        if 80 > score >= 60:
           print("CCC")
        else:
            if 60 > score >= 0:
               print("DDD")
            else:
                print("error! range:0-100")

score = int(input("score:"))
if 100 >= score >= 90:
    print("AAA")
elif 90 > score >= 80:
    print("BBB")
elif 80 > score >= 60:
    print("CCC")
elif 60 > score >= 0:
    print("DDD")
else:
    print("error! range: 0-100")

>>> test1 = ["aaa","bbb","ccc","ddd"]
>>> for i in test1:
    if i == "aaa":
        print(i.upper())
    else:
        print(i.title())

        
AAA
Bbb
Ccc
Ddd
>>> for i in test1:
    if i == "bbb":
        print(i.upper())
    else:
        print("_".join(i))

        
a_a_a
BBB
c_c_c
d_d_d

>>> test1 = ["aaa","bbb","ccc","ddd"]
>>> for i in test1:
    if i == "ccc":
        print(i.upper())
    else:
        print(i.replace("a","xxx"))

        
xxxxxxxxx
bbb
CCC
ddd
>>> for i in test1:
    if i == "aaa" or i == "bbb":
        print("+".join(i))
    else:
        print(i.title())

        
a+a+a
b+b+b
Ccc
Ddd