Python 流程控制

x = 50
y = 60

if x > y:            # >為關係運算子
    print("x>y")

x = 50
y = 60

if x > y:
    print("x>y")
else:
    print("x<y")

score = float(input("請輸入成績分數: "))

if score >= 90:
    print("優等")
elif score < 90 and score >= 80:
    print("甲等")
elif score < 80 and score >= 70:
    print("乙等")
elif score < 70 and score >= 60:
    print("丙等")
else:
    print("不及格")    

for i in range(5):
    print(i)
    
list1 = ["貓", "狗", "花", "鳥"]
for name in list1:
    print(name) 


for i in range(5):
    if i ==   3:
        break    #break（停止迴圈）
    print(i)
# 執行結果：到3時停止迴圈
# 0
# 1
# 2


for i in range(5):
    if i ==   3:
        continue  #continue（跳過這次，繼續執行下個循環）
    print(i)
# 執行結果：少印5
# 0
# 1
# 2
# 4

for i in range(10):
    if i ==   5:
        pass        # 尚未要撰寫程式，只是跳過 i==5 狀況下要處理的內容。 
    print(i)        # i==5 時仍然會列印出來。

range(5) # 0,1,2,3,4
range(5, 10) # 5,6,7,8,9
range(5, 10, 2) # 5,7,9  每隔2

i = 0
while i<5:
    print(i)
    i = i + 1


while True:
    num = int(input("number: "))
    if num == -1:
        break            # break 跳出迴圈

    print(num)