python判断

a = 2
b = 1
if a > b:
    print(a)
else:
    print(b)

多个if语句
a = 2
b = 1
if a > b:
    print(a)
elif a == b:
    print(b)
elif a < b:
    print(a)

三元表达式
print(a if a > b else b) #打印a如果a大于b的话，否则打印b

循环

有2种方式，for x in list,tutle，另一种是while循环

打印1到100的整数和
sum = 0
for i in range(1, 101):
    sum += i
print(sum)

sum = 0
i = 0
while i < 101:
    sum += i
    i += 1
print(sum)

break和continue，break是跳出当前循环，而continue是跳过本次循环，开启下一次循环
sum = 0
i = 0
while i < 101:
    if i % 2 == 0: #跳过偶数，求出奇数和
        i += 1
        continue
    else:
        sum += i
        i += 1

print(sum)

sum = 0
i = 0
while i < 101:
    if i % 2 == 0:
        i += 1
        break
    else:
        sum += i
        i += 1
print("i的值为:", i) #最后i的值是1
print(sum)