DAY 03 - if 陳述句

tags: python教學 print結尾語 if/else 九九乘法表

縮排

在python中，縮排就跟C語言的大括號一樣

age = 21

if age >= 20 :
    print("可以投票")
else :
    print("不能投票")

BMI計算機

#輸入

weight = int(input("輸入體重(公斤)"))
height = int(input("輸入身高(公分)"))

#換公尺
sq_h = (height / 100) ** 2
BMI = weight / sq_h

if 數字大小判斷

if BMI < 18.5 :
    print("異常:過輕")

elif BMI < 24:
    print("正常")

else:
    print("異常",end=':')

    if BMI < 27:
        print("過重")
    elif BMI < 30:
        print("輕度肥胖")
    elif BMI < 35:
        print("中度肥胖")
    else:
        print("重度肥胖")

---

補充 - print結尾語

print函數定義(看看就好)

print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)

print目前常用到的只有結尾語
通常print沒有設定結尾語時，預設是使用\n(換行符號)
所以可以將print("",end = 'XX')裡的XX換成其他東西
e.g.

for i in range(1,10):
  print(i,end = ',')

for i in range(1,10):
  print(i,end = ' ')

輸出結果:

1,2,3,4,5,6,7,8,9,
1 2 3 4 5 6 7 8 9

---

and & or

a = 5
b = 6
c = 8

if a>c and b>a:
  print("兩個敘述句「都」對")

if a>c or b>a:
  print("兩個敘述句「至少有一個」對")

---

補充 - 數字比較

python規範比較寬鬆 所以可以使用 a < b < c 這種連續比較數值的方式
e.g.

score = 87
if score == 100:
  print("A+")
elif 90<=score<100:
    print("A")
elif 80<=score<90:
    print("B")
elif 70<=score<80:
    print("C")
elif 60<=score<70:
    print("D")
else:
    print("F")

---

if應用 - 偵測串列內是否有值

#空串列
students = []
if students:  #偵測串列裡是否有值
  print("有學生")
else:
  print("串列是空的")

if應用 - 偵測某值是否有在串列中

students = ["jack","rose","bonny","stan"]
studentA = "alan"

if studentA in students: 
  print("alan在串列中")
else:
  print("alan不在串列中")

---

inClass practice - 九九乘法表

輸出結果：

1 * 1 = 1  1 * 2 = 2  1 * 3 = 3  1 * 4 = 4  1 * 5 = 5  1 * 6 = 6  1 * 7 = 7  1 * 8 = 8  1 * 9 = 9  

2 * 1 = 2  2 * 2 = 4  2 * 3 = 6  2 * 4 = 8  2 * 5 = 10  2 * 6 = 12  2 * 7 = 14  2 * 8 = 16  2 * 9 = 18  

3 * 1 = 3  3 * 2 = 6  3 * 3 = 9  3 * 4 = 12  3 * 5 = 15  3 * 6 = 18  3 * 7 = 21  3 * 8 = 24  3 * 9 = 27  

4 * 1 = 4  4 * 2 = 8  4 * 3 = 12  4 * 4 = 16  4 * 5 = 20  4 * 6 = 24  4 * 7 = 28  4 * 8 = 32  4 * 9 = 36  

5 * 1 = 5  5 * 2 = 10  5 * 3 = 15  5 * 4 = 20  5 * 5 = 25  5 * 6 = 30  5 * 7 = 35  5 * 8 = 40  5 * 9 = 45  

6 * 1 = 6  6 * 2 = 12  6 * 3 = 18  6 * 4 = 24  6 * 5 = 30  6 * 6 = 36  6 * 7 = 42  6 * 8 = 48  6 * 9 = 54  

7 * 1 = 7  7 * 2 = 14  7 * 3 = 21  7 * 4 = 28  7 * 5 = 35  7 * 6 = 42  7 * 7 = 49  7 * 8 = 56  7 * 9 = 63  

8 * 1 = 8  8 * 2 = 16  8 * 3 = 24  8 * 4 = 32  8 * 5 = 40  8 * 6 = 48  8 * 7 = 56  8 * 8 = 64  8 * 9 = 72  

9 * 1 = 9  9 * 2 = 18  9 * 3 = 27  9 * 4 = 36  9 * 5 = 45  9 * 6 = 54  9 * 7 = 63  9 * 8 = 72  9 * 9 = 81

小提示

i," * ",j," = ",i*j

解答

for i in range(1, 10): # i從1到9
    for j in range(1, 10): # j從1到9
        print(i ,'*', j ,'=' ,i*j,end=" ")  #印出i*j=i*j 

---

Homework - 印星星

每隔一行多兩個*
輸出結果：

*
***
*****
*******

解答

7/10

Homework - 加法

https://zerojudge.tw/ShowProblem?problemid=a002