# Python common script summary

1. Bubble sorting

```lis = [56,12,1,8,354,10,100,34,56,7,23,456,234,-58]

def sortport():
for i in range(len(lis)-1):
for j in range(len(lis)-1-i):
if lis[j]>lis[j+1]:
lis[j],lis[j+1] = lis[j+1],lis[j]
return lis
if __name__ == '__main__':
sortport()
print(lis)
```

2. Method to calculate the n th power of x

```def power(x,n):
s = 1
while n > 0:
n=n-1
s=s*x
return s

print(power(2,4))
```

3. Calculate a*a + b*b + c*c +

```def calc(*numbers):
sum=0
for n in numbers:
sum=sum+n*n
return sum
print(calc(2,4,5))
```

4. Calculate factorial n!

```#Method 1
def fac():
num = int(input("Please enter a number:"))
factorial = 1
#See if the number is negative, 0 or positive
if num<0:
print("Sorry, negative numbers don't have factorials")
elif num == 0:
print("0 The factorial of is 1")
else:
for i in range(1,num+1):
factorial = factorial*i
print("%d The factorial is%d"%(num,factorial))
if __name__ == '__main__':
fac()
```

```#Method two
def fac():
num = int(input("Please enter a number:"))
#See if the number is negative, 0 or positive
if num<0:
print("Sorry, negative numbers don't have factorials")
elif num == 0:
print("0 The factorial of is 1")
else:
print("%d The factorial is%d"%(num,factorial(num)))
def factorial(n):
result = n
for i in range(1,n):
result=result*i
return result

if __name__ == '__main__':
fac()
```

```#Method three
def fac():
num = int(input("Please enter a number:"))
#See if the number is negative, 0 or positive
if num<0:
print("Sorry, negative numbers don't have factorials")
elif num == 0:
print("0 The factorial of is 1")
else:
print("%d The factorial is%d"%(num,fact(num)))

def fact(n):
if n == 1:
return 1
return n * fact(n - 1)

if __name__ == '__main__':
fac()
```

5. List all files and directory names under the current directory

```import os

for d in os.listdir('.'):
print(d)
```

6. Change all strings in a list to lowercase:

```L = ['Hello','World','IBM','Apple']
print([s.lower()for s in L])#All strings in the whole list become lowercase, and a list is returned
for s in L:
s=s.lower()
print(s)     #Change each string in the list to lowercase and return each string
```

7. Output the paths of all files and folders under a certain path

```import os
def print_dir():
filepath = input("Please enter a path")
if filepath == "":
else:
for i in os.listdir(filepath):         #Get the list of files and subdirectories in the directory
print(os.path.join(filepath,i))     #Combine paths
print(print_dir())
```

8. Output a path and all file paths under its subdirectories

```import os
def show_dir(filepath):
for i in os.listdir(filepath):
path = (os.path.join(filepath,i))
print(path)
if os.path.isdir(path):               #isdir() to determine whether it is a directory
show_dir(path)                    #If directory, use recursive method
show_dir(filepath)
```

9. Output a path and all files with. html suffix under its subdirectory

```import os
def print_dir(filepath):
for i in os.listdir(filepath):
path = os.path.join(filepath,i)
if os.path.isdir(path):                   #isdir() to determine whether it is a directory
print_dir(path)                       #If directory, use recursive method
if path.endswith(".html"):
print(path)
print_dir(filepath)
```

10. Reverse the key value of the original dictionary and produce a new dictionary

```dict1 = {"A":"a","B":"b","C":"c"}
dict2 = {y:x for x,y in dict1.items()}
print(dict2)
#The output result is {'a': 'a', 'B':'b ',' C ':'c'}
```

11. Print multiplication table

```for i in range(1,10):
for j in range(1,i+1):
print('%d x %d = %d \t'%(j,i,i*j),end='')   #By specifying the value of the end parameter, you can cancel the output of carriage return at the end to achieve no line wrapping.
print()
```

12. Replace all 3 in the list as 3a

```num = ["harden","lampard",3,34,45,56,76,87,78,45,3,3,3,87686,98,76]
print(num.count(3))
print(num.index(3))
for i in range(num.count(3)):      #Get 3 occurrences
ele_index = num.index(3)        #Get the coordinates of the first 3 occurrences
num[ele_index]="3a"            #Amendment 3 is 3a
print(num)
```

13. Print each name

```L = ["James","Meng","Xin"]
for i in range(len(L)):
print("Hello.%s"%L[i])
```

14. Merger and de duplication

```list1 = [2,3,8,4,9,5,6]
list2 = [5,6,10,17,11,2]
list3 = list1 + list2
print(list3)              #Do not duplicate, only combine two lists
print(set(list3))         #De duplication, type set needs to be converted to list
print(list(set(list3)))
```

15. Two ways of randomly generating verification code (alphanumeric)

```import random
list1=[]
for i in range(65,91):
list1.append(chr(i))        #Append asii to the empty list through for loop traversal
for j in range (97,123):
list1.append(chr(j))
for k in range(48,58):
list1.append(chr(k))
ma = random.sample(list1,6)
print(ma)                      #List obtained
ma = ''.join(ma)              #Convert list to string
print(ma)
```

16. Calculation of square root

```num = float(input('Please enter a number:'))
num_sqrt = num ** 0.5
print('%0.2f The square root of is%0.2f'%(num,num_sqrt))
```

17. Judge whether the string is only composed of numbers

```#Method 1
def is_number(s):
try:
float(s)
return  True
except ValueError:
pass
try:
import unicodedata
unicodedata.numeric(s)
return  True
except(TypeError,ValueError):
pass
return False
t="a12d3"
print(is_number(t))
```

```#Method two
t = "q123"
print(t.isdigit())   #Check whether the string is composed of numbers only
```

```#Method three
t = "123"
print(t.isnumeric())   #This method is only for unicode objects
```

18. Judge odd and even numbers

```#Method 1
num = int(input('Please enter a number:'))
if (num % 2) == 0:
print("{0}Even numbers".format(num))
else:
print("{0}It's odd.".format(num))
```

```#Method two
while True:
try:
num = int(input('Please enter an integer:'))      #Judge whether the input is an integer, not a pure number, and need to be re entered
except ValueError:
print("The input is not an integer!")
continue
if (num % 2) == 0:
print("{0}Even numbers".format(num))
else:
print("{0}It's odd.".format(num))
break
```

19. Determine leap year

```#Method 1
year = int(input("Please enter a year:"))
if (year % 4) == 0:
if (year % 100) == 0:
if(year % 400) ==0:
print("{0}It is a leap year.".format(year))       #Leap years are the ones that can be divided by 400
else:
print("{0}Not a leap year.".format(year))
else:
print("{0}It is a leap year.".format(year))           #Leap years are those that can be divided by four
else:
print("{0}Not a leap year.".format(year))
```

```#Method two
year = int(input("Please enter a year:"))
if (year % 4) == 0 and (year % 100)!=0 or (year % 400) == 0:
print("{0}It is a leap year.".format(year))
else:
print("{0}Not a leap year.".format(year))
```

```#Method three
import calendar
year = int(input("Please enter the year:"))
check_year=calendar.isleap(year)
if check_year == True:
print("%d It is a leap year."%year)
else:
print("%d It's the year of peace."%year)
```

20. Get the maximum value

```N = int(input('Enter the number of numbers to compare:'))
print("Please enter the number to compare:")
num = []
for i in range(1,N+1):
temp = int(input('Please input number 1.%d Number:'%i))
num.append(temp)
print('The number you entered is:',num)
print('The maximum value is:',max(num))
```

```N = int(input('Enter the number of numbers to compare:\n'))
num = [int(input('Please input number 1.%d Number:\n'%i))for i in range(1,N+1)]
print('The number you entered is:',num)
print('The maximum value is:',max(num))
```

Keywords: Python

Added by Steven_belfast on Mon, 02 Dec 2019 19:59:36 +0200