一、程序的分支結構

二、身體質量指數BMI

#CalBIv1.py
height,weight = eval((input("請輸入身高(米)和體重\(公斤)[逗號隔開]:")))
bmi = weight / pow(height,2)
print("BMI數值為:{:.2f}".format(bmi))
who,nat = "",""
if bmi<18.5:
    who,nat = "偏瘦", "偏瘦"
elif 18.5<=bmi<25:
    who,nat = "正常","正常"
elif 24<=bmi<=25:
    who,nat 
 
= "正常","偏胖"
elif 25<=bmi<28:
    who,nat = "偏胖","偏胖"
elif 28<=bmi<30:
    who,nat = "偏胖","肥胖"
else:
    who,nat = "肥胖","肥胖"
print("BMI指標為:國際‘{0}‘,國家‘{1}‘".format(who,nat))
                     

三、程序的循環結構

遍歷循環

計數循環
for i in renge(N):
    <語句塊>
for i in range(M,N,K):
    M,起點，N,終點,K,步長
 
for c in s:
    s字符串，c，s中的每個字符

for c in "Python123":
print(c,end=",")

P,y,t,h,o,n,1,2,3,

for item in ls:

for item in [123,"PY",456]:
print(item,end=",")

123,PY,456,

for line in fi:

無限循環

while <條件>:
       <語句塊>

循環控制保留字

break,continue

循環的高級用法

四、random庫

使用隨機數的標準庫
 
基本隨機數函數：seed(),random()
隨機數種子
import random
random

randint(a,b) 生成ab之間的整數
randrange(m,n,k)生成一個mn之間以k為步長的整數
getrandbits(k) 生成一個k比特長的隨機整數
uniform(a,b) ab之間的隨機小數
choice(seq) 從序列seq中隨機選擇一個元素
shuffle(seq) 將序列seq中元素隨機排列，返回打亂後的序列

五、圓周率的計算

#CalPiV2.py
from random import random
from time import perf_counter
DARTS = 1000*1000*10
hits= 0.0
start = perf_counter()
for i in range(1,DARTS+1):
    x,y = random(),random()
    dist = pow(x**2+y**2,0.5)
    if dist <= 1.0:
        hits = hits+1  
pi = 4*(hits/DARTS)
print("圓周率值是：{}".format(pi))
print("運行時間是：{:.5f}s".format(perf_counter()-start))

Python第四章（北理國家精品課 嵩天等）