Python documentation file io

Python provides basic functions and methods necessary to manipulate files by default. You can do most of the file manipulation using a file object. Before you can read or write a file, you have to open it using Python's built-in open function. This function creates a file object, which would be utilized to call other support methods associated with it. A complete list of possible values is given below in the table.

This is an optional parameter and the default file access mode is read r. If the buffering value is 1, line buffering is performed while accessing a file. If you specify the buffering value as an integer greater than 1, then buffering action is performed with the indicated buffer size. If negative, the buffer size is the system default default behavior.

Opens a file for reading only. The file pointer is placed at the beginning of the file. This is the default mode. Opens a file for reading only in binary format. Opens a file for both reading and writing in binary format. The file pointer placed at the beginning of the file. Opens a file for writing only. Overwrites the file if the file exists. If the file does not exist, creates a new file for writing. Opens a file for writing only in binary format. Opens a file for both writing and reading.

Python os module provides methods that help you perform file-processing operations, such as renaming and deleting files. You can use the remove method to delete files by supplying the name of the file to be deleted as the argument.

All files are contained within various directories, and Python has no problem handling these too. The os module has several methods that help you create, remove, and change directories. You can use the mkdir method of the os module to create directories in the current directory. You need to supply an argument to this method which contains the name of the directory to be created.

You can use the chdir method to change the current directory. The chdir method takes an argument, which is the name of the directory that you want to make the current directory.

It is required to give fully qualified name of the directory, otherwise it would search for that directory in the current directory. File Object Methods : The file object provides functions to manipulate files.

OS Object Methods : This provides methods to process files as well as directories. Malhar Lathkar. Arnab Chakraborty. In28Minutes Official. Eduonix Learning Solutions. Lets Kode It. Abhilash Nelson. Previous Page. Next Page. Live Demo. Useful Video Courses. A buffered binary stream providing higher-level access to a readable, non seekable RawIOBase raw binary stream.

When reading data from this object, a larger amount of data may be requested from the underlying raw stream, and kept in an internal buffer. The buffered data can then be returned directly on subsequent reads. Return bytes from the stream without advancing the position. At most one single read on the raw stream is done to satisfy the call. The number of bytes returned may be less or more than requested. Read and return size bytes, or if size is not given or negative, until EOF or if the read call would block in non-blocking mode.

Read and return up to size bytes with only one call on the raw stream. If at least one byte is buffered, only buffered bytes are returned. Otherwise, one raw stream read call is made. A buffered binary stream providing higher-level access to a writeable, non seekable RawIOBase raw binary stream. When writing to this object, data is normally placed into an internal buffer. The buffer will be written out to the underlying RawIOBase object under various conditions, including:. The constructor creates a BufferedWriter for the given writeable raw stream.

Force bytes held in the buffer into the raw stream. A BlockingIOError should be raised if the raw stream blocks. Write the bytes-like object , b , and return the number of bytes written.

When in non-blocking mode, a BlockingIOError is raised if the buffer needs to be written out but the raw stream blocks. A buffered binary stream providing higher-level access to a seekable RawIOBase raw binary stream. It inherits BufferedReader and BufferedWriter. The constructor creates a reader and writer for a seekable raw stream, given in the first argument.

In addition, seek and tell are guaranteed to be implemented. A buffered binary stream providing higher-level access to two non seekable RawIOBase raw binary streams—one readable, the other writeable. BufferedRWPair does not attempt to synchronize accesses to its underlying raw streams.

You should not pass it the same object as reader and writer; use BufferedRandom instead. Base class for text streams. A string, a tuple of strings, or None , indicating the newlines translated so far. Depending on the implementation and the initial constructor flags, this may not be available. Separate the underlying binary buffer from the TextIOBase and return it. After the underlying buffer has been detached, the TextIOBase is in an unusable state. Read and return at most size characters from the stream as a single str.

If size is negative or None , reads until EOF. Read until newline or EOF and return a single str. If the stream is already at EOF, an empty string is returned. Change the stream position to the given offset. Behaviour depends on the whence parameter. Any other offset value produces undefined behaviour. Return the current stream position as an opaque number. The number does not usually represent a number of bytes in the underlying binary storage.

A buffered text stream providing higher-level access to a BufferedIOBase buffered binary stream. It inherits TextIOBase. It defaults to locale. Pass 'strict' to raise a ValueError exception if there is an encoding error the default of None has the same effect , or pass 'ignore' to ignore errors.

Note that ignoring encoding errors can lead to data loss. Any other error handling name that has been registered with codecs. It works as follows:. When reading input from the stream, if newline is None , universal newlines mode is enabled.

If newline is '' , universal newlines mode is enabled, but line endings are returned to the caller untranslated. If newline has any of the other legal values, input lines are only terminated by the given string, and the line ending is returned to the caller untranslated. It is not possible to change the encoding or newline if some data has already been read from the stream.

On the other hand, changing encoding after write is possible. A text stream using an in-memory text buffer. The text buffer is discarded when the close method is called. If newline translation is enabled, newlines will be encoded as if by write.

The stream is positioned at the start of the buffer. Return a str containing the entire contents of the buffer. Newlines are decoded as if by read , although the stream position is not changed. A helper codec that decodes newlines for universal newlines mode. It inherits codecs. Interacting with the file is then done by working with the variable that you specify after as. This is called a file object. To get the complete content of a file use its read method like this:.

In some tutorials and also production code you may find something along the lines of this to interact with a file:. This is kind of the old style of working with files when the with statement did not exist yet. It has the huge downside that you have to take care about closing the file.