Python 的if语句

for str in lib:
    if str != 'efg'"":    #判断两个值是否不等
        print(str.upper())
    else:
        print(str.title())
'''
ABC
Efg
HIGK
LMN
'''
#and 表示 ‘与’
lib1 = list(range(2,20,3))
print(lib1)
for aa in lib1:
    if aa>=6 and aa<=11:
        print('%d_'%aa)
    else:
        print(aa)
'''
[2, 5, 8, 11, 14, 17]
2
5
8_
11_
14
17
'''
#or 表示 ‘或’；elif + 判断添加
print(lib1)
for nn in lib1:
    if nn < 6  or nn>=14:
        print('_%d'%nn)
    elif nn == 11:
        print('%d_'%nn)
    else:
        print(nn)
'''
[2, 5, 8, 11, 14, 17]
_2
_5
8
11_
_14
_17
'''

#用in 判断元素是否在列表中
T = 8 in lib1
T1 = 10 in lib1
print(T)
print(T1)
'''
True
False
'''


car = 'subaru'
print("Is car == 'subaru'? I predict True.")
print(car == 'subaru')
print("\nIs car == 'audi'? I predict False.")
print(car == 'audi')
'''
Is car == 'subaru'? I predict True.
True

Is car == 'audi'? I predict False.
False
'''

#列表是否为空，为空if lib 返回False，非空返回True
lib2 = []
if lib2:
    print("非空")
else:
    print('空')
#空