File Operations In Python

 

File Operations

• How to Create / Open File   open()

           file_name = open(path/file_name, file_mode)

           by default file mode is "rt"

            mode as "w", 'a" and "x" will create file.

• How to Close File   close()

            file_name.close()

Example :  create file

• program to create file

 #program to create file for first time

 file = open("my_file.txt", "x")
 print(file)
 print("file created")
 file.close()

 #Output

 <_io.TextIOWrapper name='my_file.txt' mode='x' encoding='cp1252'>
 file created

• program to create same file 2nd time, open() will return File_Exists_Error

 #program to create file if already exist

 file = open("my_file.txt", "x")
 print(file)
 print("file created")
 file.close()

 #Output

 Traceback (most recent call last):
   File "C:/Self_Practice_Er_M_S_Dandyan/Python/Pycharm/xml/main.py", line 3, in <module>
     file = open("my_file.txt", "x")
 FileExistsError: [Errno 17] File exists: 'my_file.txt'

Example : program to open file in read mode

• when file exist

 #program to open file in read mode if file exist

 file = open("my_file.txt", "r")
 print(file)
 print("file opened successfully")
 file.close()

 #Output

 <_io.TextIOWrapper name='my_file.txt' mode='r' encoding='cp1252'>
 file opened successfully

• when file does not exist, open() will return File_Not_Found_Error

 #program to open file in read mode if file exist

 file = open("my_file.txt", "r")
 print(file)
 print("file opened successfully")
 file.close()

 #Output

 Traceback (most recent call last):
   File "C:/Self_Practice_Er_M_S_Dandyan/Python/Pycharm/xml/main.py", line 3, in <module>
     file = open("my_file.txt", "r")
 FileNotFoundError: [Errno 2] No such file or directory: 'my_file.txt'

Example : program to open file in write mode

• if file not present, it will create new file and open the file.

• if file exist, it will open file and delete all the data from the file.

 #program 

 file = open("my_file.txt", "w")
 print(file)
 print("file opened successfully")
 file.close()

 #Output

 <_io.TextIOWrapper name='my_file.txt' mode='w' encoding='cp1252'>
 file opened successfully

Example : program to open file in append mode

• if file not present, it will create new file and open the file.

• if file exist, it will open file and open the file without deleting the previous data and the new dat will be added to end of existing data.

 #program 

 file = open("my_file.txt", "a")
 print(file)
 print("file opened successfully")
 file.close()

 #Output

 <_io.TextIOWrapper name='my_file.txt' mode='a' encoding='cp1252'>
 file opened successfully

• How to Read data in File      read()

         data_in_file = file_name.read()

 #program 

 file = open("my_file.txt", "r")
 print("file opened successfully")

 data_in_File = file.read()
 print("below is the data inside the file\n\n",data_in_File)

 file.close()

 #Output

 file opened successfully
 below is the data inside the file

  Hi, this is Techno Xpresss.
 This is a sample file to read.

• How to Write data in File      write()

         file_name.write()

 #program 

 file = open("my_file.txt", "r")
 file_1 = open("my_file_1.txt", "w")
 print("file opened successfully")

 data_in_File = file.read()
 file_1.write(data_in_File)
 print("data written successfully")

 file.close()
 file_1.close()

 file_1 = open("my_file_1.txt", "r")
 data_in_File = file_1.read()
 print("\n\nbelow is the data inside the file_1\n\n",data_in_File)
 file_1.close()

 #Output

 file opened successfully
 data written successfully

 below is the data inside the file_1

 Hi, this is Techno Xpresss.
 This is a sample file to read.