Which of the following command is used to open a file in write mode only?
When we want to read from or write to a file, we need to open it first. When we are done, it needs to be closed so that the resources that are tied with the file are freed. Show
Hence, in Python, a file operation takes place in the following order:
Opening Files in PythonIn Python, we use the 1 method to open files.To demonstrate how we open files in Python, let's suppose we have a file named 2 with the following content.Opening Files in PythonNow, let's try to open data from this file using the 1 function.
Here, we have created a file object named file1. This object can be used to work with files and directories. By default, the files are open in read mode (cannot be modified). The code above is equivalent to
Here, we have explicitly specified the mode by passing the 4 argument which means file is opened for reading.Different Modes to Open a File in PythonModeDescription 5Open a file for reading. (default) 6Open a file for writing. Creates a new file if it does not exist or truncates the file if it exists. 7Open a file for exclusive creation. If the file already exists, the operation fails. 8Open a file for appending at the end of the file without truncating it. Creates a new file if it does not exist. 9Open in text mode. (default) 0Open in binary mode. 1Open a file for updating (reading and writing)Here's few simple examples of how to open a file in different modes,
Reading Files in PythonAfter we open a file, we use the 2 method to read its contents. For example,
Output This is a test file. Hello from the test file. In the above example, we have read the 2 file that is available in our current directory. Notice the code,
Here, 4 reads the 2 file and is stored in the read_content variable.Closing Files in PythonWhen we are done with performing operations on the file, we need to properly close the file. Closing a file will free up the resources that were tied with the file. It is done using the 6 method in Python. For example,
Output This is a test file. Hello from the test file. Here, we have used the 6 method to close the file.After we perform file operation, we should always close the file; it's a good programming practice. Exception Handling in FilesIf an exception occurs when we are performing some operation with the file, the code exits without closing the file. A safer way is to use a try...finally block. Let's see an example,
Here, we have closed the file in the 8 block as 8 always executes, and the file will be closed even if an exception occurs.Use of with...open SyntaxIn Python, we can use the 0 syntax to automatically close the file. For example,
Note: Since we don't have to worry about closing the file, make a habit of using the 0 syntax.Writing to Files in PythonThere are two things we need to remember while writing to a file.
In order to write into a file in Python, we need to open it in write mode by passing 2 inside 1 as a second argument.Suppose, we don't have a file named test2.txt. Let's see what happens if we write contents to the 4 file. 0Here, a new 4 file is created and this file will have contents specified inside the 6 method.Writing to Python FilesPython File MethodsThere are various methods available with the file object. Some of them have been used in the above examples. Here is the complete list of methods in text mode with a brief description: MethodDescriptionclose()Closes an opened file. It has no effect if the file is already closed.detach()Separates the underlying binary buffer from the 7 and returns it.fileno()Returns an integer number (file descriptor) of the file.flush()Flushes the write buffer of the file stream.isatty()Returns 8 if the file stream is interactive.read(n)Reads at most n characters from the file. Reads till end of file if it is negative or 9.readable()Returns 8 if the file stream can be read from.readline(n=-1)Reads and returns one line from the file. Reads in at most n bytes if specified.readlines(n=-1)Reads and returns a list of lines from the file. Reads in at most n bytes/characters if specified.seek(offset,from=This is a test file. Hello from the test file.1)Changes the file position to offset bytes, in reference to from (start, current, end).seekable()Returns 8 if the file stream supports random access.tell()Returns an integer that represents the current position of the file's object.truncate(size= 9)Resizes the file stream to size bytes. If size is not specified, resizes to current location.writable()Returns 8 if the file stream can be written to.write(s)Writes the string s to the file and returns the number of characters written.writelines(lines)Writes a list of lines to the file.
Which command is used to open a file?Open File Using cat Command
This is the most popular and easy way to display the file content. It simply prints the file content to the terminal.
Which of the command is used to open a file c :\ temp txt in write mode only?In C, fopen() is used to open a file in different modes. To open a file in write mode, “w” is specified.
Which of the following command is used to open a file c demo txt in read mode only in Python?The read() method:
f = open("myfiles. txt", "r") #('r') opens the text files for reading only print(f.
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