Python files and exceptions,

Python files and exceptions,
I. Reading data from a file

 

#!/usr/bin/env pythonwith open('pi') as file_object:    contents = file_object.read()    print(contents)===================================3.1415926  5212533  2324255

 

1. Read data row by row

#!/usr/bin/env pythonfilename = 'pi'with open(filename) as file_object:    for line in file_object:        print(line)===================================3.1415926  5212533  2324255

 

#!/usr/bin/env pythonfilename = 'pi'with open(filename) as file_object:    for line in file_object:        print(line.rstrip())==================3.1415926  5212533  2324255

 

2. Create a list containing the content of each row of the file

#! /Usr/bin/env pythonfilename = 'pi' with open (filename) as file_object: lines = file_object.readlines () # The readlines () method reads each row from the file, and store it in a list for line in lines: print (line. rstrip () ============================ 3.1415926 5212533

 

3. Use the File Content

#!/usr/bin/env pythonfilename = 'pi'with open(filename) as file_object:    lines = file_object.readlines()pi_string = ''for line in lines:    pi_string += line.strip()print(pi_string)print(len(pi_string))========================================3.14159265212533232425523

 

Ii. Writing files

1. Write an empty file

#!/usr/bin/env pythonfilename = 'programming.txt'with open(filename,'w') as file_object:    file_object.write("I love programming!")

2. Write multiple rows

#!/usr/bin/env pythonfilename = 'programming.txt'with open(filename,'w') as file_object:    file_object.write("I love programming!\n")    file_object.write("yes!\n")

3. attach to a file

#!/usr/bin/env pythonfilename = 'pi'with open(filename,'a') as file_object:    file_object.write("I love programming!\n")    file_object.write("yes!\n")

 

Iii. Exceptions

1. Use try-try T code block

#!/usr/bin/env pythontry:    print(5/0)except ZeroDivisionError:    print("You cant divide by zero!")