Chapter4
PM2.5 二分支 多分支 嵌套分支（选择结构学习）国标BMI 和 世界BMI圆周率计算字母 数字 空格 其它字符 出现次数统计字母 数字 空格 其它字符 出现次数统计 函数版字母 数字 空格 其它字符 出现次数统计 字典版
PM2.5 二分支 多分支 嵌套分支（选择结构学习）
PM
= eval(input("请输入 PM 数值: "))
if PM
>= 75:
print("空气存在污染，请小心！")
else:
print("空气没有污染，可以开展户外运动！")
请输入 PM 数值: 25
空气没有污染，可以开展户外运动！
PM
= eval(input("请输入PM 2.5 数值: "))
if 0 <= PM
< 35:
print("空气优质，快去户外运动！")
if 35 <= PM
< 75:
print("空气良好，适合户外活动！")
if 75 <= PM
:
print("空气污染，请小心！")
请输入PM 2.5 数值: 25
空气优质，快去户外运动！
PM
= eval(input("请输入 PM 数值: "))
if 0 <= PM
< 35:
print("空气优质，快去户外运动")
elif 35 <= PM
< 75:
print("空气质量中等，适度户外运动")
else:
print("空气存在污染，请小心！")
请输入 PM 数值: 25
空气优质，快去户外运动
国标BMI 和 世界BMI
height
, weight
= eval(input("please input height and weight: "))
bmi
= weight
/ pow(height
, 2)
print(f
'BMI value :{bmi}')
who
, dom
= "", ""
if bmi
< 18.5:
who
, dom
= "偏瘦", "偏瘦"
elif 18.5 <= bmi
< 24:
who
, dom
= "正常", "正常"
elif 24 <= bmi
< 25:
who
, dom
= "正常", "偏胖"
elif 25 <= bmi
< 28:
who
, dom
= "偏胖", "偏胖"
elif 28 <= bmi
< 30:
who
, dom
= "偏胖", "肥胖"
else:
who
, dom
= "肥胖", "肥胖"
print(f
'BMI value is : who:{who} dom:{dom}')
please input height and weight: 165,60
BMI value :0.0022038567493112946
BMI value is : who:偏瘦 dom:偏瘦
圆周率计算
from random
import random
from math
import sqrt
from time
import perf_counter
DARTS
= 10000000
hits
= 0.0
perf_counter
()
for i
in range(1, DARTS
+ 1):
x
, y
= random
(), random
()
dist
= sqrt
(x
** 2 + y
** 2)
if dist
<= 1.0:
hits
= hits
+ 1
PAI
= 4 * (hits
/ DARTS
)
print("π value is: {}".format(PAI
))
print("run time is: {:.5f}s".format(perf_counter
()))
π value is: 3.1400448
run time is: 179.23083s
字母 数字 空格 其它字符 出现次数统计
str_line
= input("请输入字符串:")
Letters
, number
, Space
, Other
= 0, 0, 0, 0
for char
in str_line
:
if ('a' <= char
<= 'z') or ('A' <= char
<= 'Z'):
Letters
+= 1
elif '0' <= char
<= '9':
number
+= 1
elif char
== ' ':
Space
+= 1
else:
Other
+= 1
print(f
'Letters have: {Letters}\n'
f
'Number have: {number}\n'
f
'Space have: {Space}\n'
f
'Other have: {Other}')
请输入字符串:abv123 $%^
Letters have: 3
Number have: 3
Space have: 2
Other have: 3
字母 数字 空格 其它字符 出现次数统计 函数版
str_line
= input("please input string:")
Letters
, Number
, Space
, Other
= 0, 0, 0, 0
for i
in str_line
:
if i
.isdigit
():
Number
+= 1
elif i
.isalpha
():
Letters
+= 1
elif i
== ' ':
Space
+= 1
else:
Other
+= 1
print(f
'Letters have: {Letters}\n'
f
'Number have: {Number}\n'
f
'Space have: {Space}\n'
f
'Other have: {Other}')
please input string:abc 123 %%%
Letters have: 3
Number have: 3
Space have: 2
Other have: 3
字母 数字 空格 其它字符 出现次数统计 字典版
str_line
= input("please input string:")
dic
= dict.fromkeys
(['Letters', 'Number', 'Space', 'Other'], 0)
for char
in str_line
:
if char
.isdigit
():
dic
['Number'] += 1
elif char
.isalpha
():
dic
['Letters'] += 1
elif char
== ' ':
dic
['Space'] += 1
else:
dic
['Other'] += 1
print(dic
)
please input string:abc 123 %%%
{'Letters': 3, 'Number': 3, 'Space': 2, 'Other': 3}
