Python

Posted 2022-10-30 wwqdata

函数

https://docs.python.org/3/library/functions.html

编程实例

1.打印质数

for n in range (2,100):
    if n==2:
          print(n)
          continue
for i in range (2, n):
    if (n %i) ==0:
          break
    else:
          print(n)

注意对齐

打印质数改良版

def is_prime(n):
      if(n<2):
            return False
      if(n==2):
            return True
      for m in range (2, int(n**0.5)+1):
            if(n%m)==0:
                return False
            else:
                return True
for i in range(80,110):
      if is_prime(i):
           print(i)

2.基本概念

1.from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity = "all"
11+10-9/8//7%5
‘3.14‘+3

运行结果

21.0

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-12-d1e427b7cc92> in <module>
      2 InteractiveShell.ast_node_interactivity = "all"
      3 11+10-9/8//7%5
----> 4 ‘3.14‘+3

TypeError: can only concatenate str (not "int") to str

 

2.from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity = "all"
type(3)
type(3.0)
type(range(10))
type(‘3.14‘)
type(True)
type([1,2,3])
type(‘a‘:1,‘b‘:2,‘c‘:3)

type((1,2,3))
type(1,2,3)

int

float

range

str

bool

list

dict

tuple
set

 

3.from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity = "all"
‘Python‘+‘Awesome‘
‘Python‘,‘Awesome‘
‘Python, ‘+‘Awesome! ‘ * 3
‘o‘ in ‘Awesome‘ and ‘o‘ not in ‘Python‘

运行结果：
‘PythonAwesome‘

(‘Python‘, ‘Awesome‘)

‘Python, Awesome! Awesome! Awesome! ‘

False


4.

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity = "all"
‘A‘>‘a‘
ord(‘A‘)
ord(‘a‘)运行结果：

false

65

97

 

5.from IPython.core.interactiveshell import InteractiveShellInteractiveShell.ast_node_interactivity = "all"
a_list=[1,2,3,4,5]
b_list=[1,2,3,5]
c_list=[‘aba‘,‘bob‘, ‘cindy‘, ‘dude‘, ‘eric‘]
a_list>b_list
10 not in a_list
‘aba‘in c_list

运行结果：

False

True

True

6.print(‘Hello‘,‘Jack‘,‘Mike‘,‘...‘,‘and all you guys‘)

Hello Jack Mike ... and all you guys

7.

name=‘ANN‘
age=‘22‘
print(f‘name is age years old.‘)

ANN is 22 years old.


8.

import sys
print(‘Hello‘,‘World‘)
print(‘Hello‘,‘World‘,sep=‘ ‘,end=‘\n‘,file=sys.stdout,flush=False)
print(‘Hello‘,‘World‘,sep=‘-‘,end=‘\t‘)
print(‘Hello‘,‘World‘,sep=‘~‘)
print(‘Hello‘,‘World‘,sep=‘\n‘)

Hello World
Hello World
Hello-World	Hello~World
Hello
World


9.print(print(1))
1
None


10.

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
sorted(‘abcd‘)
sorted(‘abcd‘,reverse=True)

[‘a‘, ‘b‘, ‘c‘, ‘d‘]

[‘d‘, ‘c‘, ‘b‘, ‘a‘]

11.

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
divmod(11,3)
a,b=divmod(11,3)
a
b

(3,2)

3

2

 

 

12.

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
pow(2,3)
pow(2,3,4)

8

0

//pow(2,3,4):2^3%4

 

 

13.

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
bool()
bool(3.14159)
bool(-3.14159)
bool(1==2)
bool(None)

False

True

True

False

False


14.

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
int(‘3‘)
float(‘3‘)
int(3.14158)
str(‘3.14159‘)33.03‘3.14159‘

 

15.age=int(input(‘‘‘Please tell me your age :an int number e.g. 22‘‘‘))
if age<18:
print(‘sorry‘)
else:
print(‘enjoy‘)

Please tell me your age :an int number e.g. 22 18

 enjoy

16.

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
‘He said,it\‘s fine.‘
"He said,it‘s fine"
"He said,it\‘s fine"不能用‘He said,it‘s fine.‘ 编译器会从it后的‘截断

 

 

17.s=‘Python‘
for char in s:
print(s.index(char),char)

0 P
1 y
2 t
3 h
4 o
5 n

18.from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
s=‘python‘
s[1]
s[2:]
s[2:5]
s[:5]
s[1:5:2]‘y‘‘thon‘‘tho‘‘pytho‘‘yh‘from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
ord(‘\n‘)
ord(‘\t‘)
ord(‘\r‘)
chr(65)
s=input(‘please follow the number3.14:‘)
int(‘3‘)
float(s)*9
len(s)
print(s*3)10913‘A‘

please follow the number3.14: 3.14

3

28.26

4

3.143.143.14

 

 

19.

from IPython.core.interactiveshell import InteractiveShell
InteractiveShell.ast_node_interactivity="all"
s=‘Now is better than ever‘
s.capitalize()
s.title()s.swapcase()
s.title().swapcase()

‘Now is better than ever‘

‘Now Is Better Than Ever‘

‘nOW IS BETTER THAN EVER‘

‘nOW iS bETTER tHAN eVER‘