Strings are an array of Unicode code characters. Show
Binary is a base-2 number system consisting of 0’s and 1’s that computers understand. The computer sees strings in binary format, i.e., ‘H’=1001000. The string, as seen by the computer, is a binary number that is an ASCCI value( Decimal number) of the string converted to binary. String to binaryTo convert a string to binary, we first appendjoin the string’s individual ASCII values to a list (
Binary to stringIn order to pass a list of binary numbers to the function, we first convert the individual numbers to ASCII value by binary to decimal (i.e., 1001000 = 72 , 1100101 = 101).
Finally, the string is appendedadded to an empty string ( These functions can be now used to convert string to binary and vice-versa.
CONTRIBUTOR Vivek Tangirala Source code: Lib/io.py Overview¶The
Independent of its category, each concrete stream object will also have various capabilities: it can be read-only, write-only, or read-write. It can also allow arbitrary random access (seeking forwards or backwards to any location), or only sequential access (for example in the case of a socket or pipe). All streams are careful about the type of data you give to them. For example giving a Changed in version 3.3: Operations that used to raise Text I/O¶Text I/O expects and produces The easiest way to create a text stream is with f = open("myfile.txt", "r", encoding="utf-8") In-memory text streams are also available as
f = io.StringIO("some initial text data") The text stream API is described in detail in the documentation of Binary I/O¶Binary I/O (also called buffered I/O) expects bytes-like objects and produces The easiest way to create a binary stream is with f = open("myfile.jpg", "rb") In-memory binary streams are also available as
f = io.BytesIO(b"some initial binary data: \x00\x01") The binary stream API is described in detail in the docs of Other library modules may provide additional ways to create text or binary streams. See
Raw I/O¶Raw I/O (also called unbuffered I/O) is generally used as a low-level building-block for binary and text streams; it is rarely useful to directly manipulate a raw stream from user code. Nevertheless, you can create a raw stream by opening a file in binary mode with buffering disabled: f = open("myfile.jpg", "rb", buffering=0) The raw stream API is described in detail in the docs of Text Encoding¶The default encoding of However, many developers forget to specify the encoding when opening text files encoded in UTF-8 (e.g. JSON, TOML, Markdown, etc…) since most Unix platforms use UTF-8 locale by default. This causes bugs because the locale encoding is not UTF-8 for most Windows users. For example: # May not work on Windows when non-ASCII characters in the file. with open("README.md") as f: long_description = f.read() Additionally, while there is no concrete plan as of yet, Python may change the default text file encoding to UTF-8 in the future. Accordingly, it is highly recommended that you specify the encoding
explicitly when opening text files. If you want to use UTF-8, pass When you need to run existing code on Windows that attempts to open UTF-8 files using the default locale encoding, you can enable the UTF-8 mode. See UTF-8 mode on Windows. Opt-in EncodingWarning¶New in version 3.10: See PEP 597 for more details. To find where the default locale encoding is used, you can enable the If you are providing an API that uses High-level Module Interface¶io. DEFAULT_BUFFER_SIZE ¶An int containing the default buffer size used by the module’s buffered I/O classes. io. open (file, mode='r', buffering=- 1, encoding=None, errors=None, newline=None,
closefd=True, opener=None)¶This is an alias for the builtin This function raises an
auditing event io. open_code (path)¶
Opens the provided file with mode
The behavior of this function may be overridden by an earlier call to the
New in version 3.8. io. text_encoding (encoding, stacklevel=2, /)¶This is a helper function for callables that use
This function returns encoding if it is not This function emits an def read_text(path, encoding=None): encoding = io.text_encoding(encoding) # stacklevel=2 with open(path, encoding) as f: return f.read() In this example, an See Text Encoding for more information. New in version 3.10. exceptionio. BlockingIOError ¶This is a compatibility alias for the builtin
io. UnsupportedOperation ¶An exception inheriting
Class hierarchy¶The implementation of I/O streams is organized as a hierarchy of classes. First abstract base classes (ABCs), which are used to specify the various categories of streams, then concrete classes providing the standard stream implementations.
At the top of the I/O hierarchy is the abstract base class The The The Argument names are not part of the specification, and only the arguments of The following table summarizes the ABCs provided by the
I/O Base Classes¶classio. IOBase ¶The abstract base class for all I/O classes. This class provides empty abstract implementations for many methods that derived classes can override selectively; the default implementations represent a file that cannot be read, written or seeked. Even though The basic type used for binary data read from or written to a file is Note that calling any method (even inquiries) on a closed stream is undefined. Implementations may raise
with open('spam.txt', 'w') as file: file.write('Spam and eggs!')
close ()¶Flush and close this stream. This method has no effect if the file is already closed. Once the file is closed, any operation on the file (e.g. reading or writing) will raise a As a convenience, it is allowed to call this method more than once; only the first call, however, will have an effect. closed ¶
fileno ()¶Return the underlying file descriptor (an integer) of the stream if it exists. An flush ()¶Flush the write buffers of the stream if applicable. This does nothing for read-only and non-blocking streams. isatty ()¶Return readable ()¶Return
readline (size=- 1, /)¶Read and return one line from the stream. If size is specified, at most size bytes will be read. The line terminator is always readlines (hint=-
1, /)¶Read and return a list of lines from the stream. hint can be specified to control the number of lines read: no more lines will be read if the total size (in bytes/characters) of all lines so far exceeds hint. hint values of Note that it’s already possible to iterate on file objects using seek (offset, whence=SEEK_SET, /)¶Change the stream position to the given
byte offset. offset is interpreted relative to the position indicated by whence. The default value for whence is
Return the new absolute position. New in version 3.1: The New in version 3.3: Some operating systems could support additional values, like seekable ()¶Return tell ()¶Return the current stream position. truncate (size=None,
/)¶Resize the stream to the given size in bytes (or the current position if size is not specified). The current stream position isn’t changed. This resizing can extend or reduce the current file size. In case of extension, the contents of the new file area depend on the platform (on most systems, additional bytes are zero-filled). The new file size is returned. Changed in version 3.5: Windows will now zero-fill files when extending. writable ()¶Return writelines (lines,
/)¶Write a list of lines to the stream. Line separators are not added, so it is usual for each of the lines provided to have a line separator at the end. __del__ ()¶Prepare for object destruction. io. RawIOBase ¶Base class for raw binary streams. It inherits
Raw binary streams typically provide low-level access to an underlying OS device or API, and do not try to encapsulate it in high-level primitives (this functionality is done at a higher-level in buffered binary streams and text streams, described later in this page).
read (size=- 1,
/)¶Read up to size bytes from the object and return them. As a convenience, if size is unspecified or -1, all bytes until EOF are returned. Otherwise, only one system call is ever made. Fewer than size bytes may be returned if the operating system call returns fewer than size bytes. If
0 bytes are returned, and size was not 0, this indicates end of file. If the object is in non-blocking mode and no bytes are available, The default implementation defers to readall ()¶Read and return all the bytes from the stream until EOF, using multiple calls to the stream if necessary. readinto (b,
/)¶Read bytes into a pre-allocated, writable bytes-like object b, and return the number of bytes read. For example, b might be a
write (b, /)¶Write the given
bytes-like object, b, to the underlying raw stream, and return the number of bytes written. This can be less than the length of b in bytes, depending on specifics of the underlying raw stream, and especially if it is in non-blocking mode. io. BufferedIOBase ¶Base class for binary streams that support some kind of buffering. It inherits
The main difference with In addition, those methods can raise
Besides, the
A typical
raw ¶
The underlying raw stream (a detach ()¶Separate the underlying raw stream from the buffer and return it. After the raw stream has been detached, the buffer is in an unusable state. Some buffers, like
New in version 3.1. read (size=-
1, /)¶Read and return up to size bytes. If the argument is omitted, If the argument is positive, and the underlying raw stream is not interactive, multiple raw reads may be issued to satisfy the byte count (unless EOF is reached first). But for interactive raw streams, at most one raw read will be issued, and a short result does not imply that EOF is imminent. A read1 (size=- 1, /)¶Read and return up to size bytes, with at most one call to the underlying raw stream’s
If size
is readinto (b, /)¶Read bytes into a pre-allocated, writable
bytes-like object b and return the number of bytes read. For example, b might be a Like A readinto1 (b,
/)¶Read bytes into a pre-allocated, writable bytes-like object b, using at most one call to the underlying raw stream’s
A New in version 3.5. write (b, /)¶Write the given bytes-like
object, b, and return the number of bytes written (always equal to the length of b in bytes, since if the write fails an When in non-blocking mode, a
The caller may release or mutate b after this method returns, so the implementation should only access b during the method call. Raw File I/O¶classio. FileIO (name, mode='r', closefd=True,
opener=None)¶A raw binary stream representing an OS-level file containing bytes data. It inherits The name can be one of two things:
The mode can be The A
custom opener can be used by passing a callable as opener. The underlying file descriptor for the file object is then obtained by calling opener with (name, flags). opener must return an open file descriptor (passing The newly created file is non-inheritable. See the Changed in version 3.3: The opener parameter was added. The Changed in version 3.4: The file is now non-inheritable.
mode ¶The mode as given in the constructor. name ¶The file name. This is the file descriptor of the file when no name is given in the constructor. Buffered Streams¶Buffered I/O streams provide a higher-level interface to an I/O device than raw I/O does. classio. BytesIO (initial_bytes=b'')¶A binary stream using an in-memory bytes buffer. It inherits The optional argument initial_bytes is a bytes-like object that contains initial data.
getbuffer ()¶Return a readable and writable view over the contents of the buffer without copying them. Also, mutating the view will transparently update the contents of the buffer: >>> b = io.BytesIO(b"abcdef") >>> view = b.getbuffer() >>> view[2:4] = b"56" >>> b.getvalue() b'ab56ef' Note As long as the view exists, the New in version 3.2. getvalue ()¶Return read1 (size=- 1,
/)¶In Changed in version 3.7: The size argument is now optional. readinto1 (b, /)¶In New in version 3.5. classio. BufferedReader (raw,
buffer_size=DEFAULT_BUFFER_SIZE)¶A buffered binary stream providing higher-level access to a readable, non seekable 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. The constructor creates a
peek (size=0,
/)¶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 (size=-
1, /)¶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. read1 (size=- 1,
/)¶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. Changed in version 3.7: The size argument is now optional. classio. BufferedWriter (raw, buffer_size=DEFAULT_BUFFER_SIZE)¶A buffered binary stream providing higher-level access to a writeable, non seekable
When writing to this object, data is normally placed into an internal buffer. The buffer will be written out to the underlying
The constructor creates a
flush ()¶Force bytes held in the buffer into
the raw stream. A write (b, /)¶Write the bytes-like object, b, and return the number of bytes written. When in non-blocking mode, a io. BufferedRandom (raw, buffer_size=DEFAULT_BUFFER_SIZE)¶A buffered binary stream providing higher-level access to a seekable
The constructor creates a reader and writer for a seekable raw
stream, given in the first argument. If the buffer_size is omitted it defaults to
io. BufferedRWPair (reader,
writer, buffer_size=DEFAULT_BUFFER_SIZE, /)¶A buffered binary stream providing higher-level access to two non seekable reader and writer are
Warning
Text I/O¶classio. TextIOBase ¶Base class for text streams. This class provides a character and line based interface to stream I/O. It inherits
encoding ¶The name of the encoding used to decode the stream’s bytes into strings, and to encode strings into bytes. errors ¶The error setting of the decoder or encoder. newlines ¶A string, a tuple of strings, or buffer ¶The underlying binary buffer (a detach ()¶Separate the underlying binary buffer from the
After the underlying buffer has been detached, the Some New in version 3.1. read (size=- 1,
/)¶Read and return at most size characters from the stream as a single readline (size=- 1, /)¶Read until newline or EOF and return a single If size is specified, at most size characters will be read. seek (offset, whence=SEEK_SET, /)¶Change the stream position to the given offset. Behaviour depends on the whence parameter. The default value for whence is
Return the new absolute position as an opaque number. New in version 3.1: The tell ()¶Return the current stream position as an opaque number. The number does not usually represent a number of bytes in the underlying binary storage. write (s, /)¶Write the string s to the stream and return the number of characters written. classio. TextIOWrapper (buffer, encoding=None, errors=None, newline=None, line_buffering=False,
write_through=False)¶A buffered text stream providing higher-level access to a encoding gives the name of the encoding that the stream will be decoded or encoded with. It defaults to errors is an optional string that specifies how encoding and decoding errors are to be handled. Pass newline controls how line endings are handled. It can be
If line_buffering is
If write_through is Changed in version 3.3: The write_through argument has been added. Changed in version 3.3: The default encoding is now Changed in version 3.10: The encoding argument now supports the
line_buffering ¶Whether line buffering is enabled. write_through ¶Whether writes are passed immediately to the underlying binary buffer. New in version 3.7. reconfigure (*[, encoding][, errors][, newline][, line_buffering][, write_through])¶Reconfigure this text stream using new settings for encoding, errors, newline, line_buffering and write_through. Parameters not specified keep current settings, except 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. This method does an implicit stream flush before setting the new parameters. New in version 3.7. classio. StringIO (initial_value='', newline='\n')¶A text stream using an in-memory text buffer. It inherits
The text buffer is discarded when the The initial value of the buffer can be set by providing initial_value. If newline translation is enabled, newlines will be encoded as if by
The newline argument works like that of
getvalue ()¶Return a Example usage: import io output = io.StringIO() output.write('First line.\n') print('Second line.', file=output) # Retrieve file contents -- this will be # 'First line.\nSecond line.\n' contents = output.getvalue() # Close object and discard memory buffer -- # .getvalue() will now raise an exception. output.close()class io. IncrementalNewlineDecoder ¶A helper codec that decodes newlines for universal newlines mode. It inherits
Performance¶This section discusses the performance of the provided concrete I/O implementations. Binary I/O¶By reading and writing only large chunks of data even when the user asks for a single byte, buffered I/O hides any inefficiency in calling and executing the operating system’s unbuffered I/O routines. The gain depends on the OS and the kind of I/O which is performed. For example, on some modern OSes such as Linux, unbuffered disk I/O can be as fast as buffered I/O. The bottom line, however, is that buffered I/O offers predictable performance regardless of the platform and the backing device. Therefore, it is almost always preferable to use buffered I/O rather than unbuffered I/O for binary data. Text I/O¶Text I/O over a binary storage (such as a file) is significantly slower than binary I/O over the same
storage, because it requires conversions between unicode and binary data using a character codec. This can become noticeable handling huge amounts of text data like large log files. Also,
Multi-threading¶
Binary buffered objects (instances of
Reentrancy¶Binary buffered objects (instances of The above implicitly extends to text files, since the How do I convert a string to a binary file in Python?How to write to a binary file in Python. file = open("sample.bin", "wb"). file. write(b"This binary string will be written to sample.bin"). file. close(). Can we convert string to binary in Python?To convert a string to binary, we first append the string's individual ASCII values to a list ( l ) using the ord(_string) function. This function gives the ASCII value of the string (i.e., ord(H) = 72 , ord(e) = 101). Then, from the list of ASCII values we can convert them to binary using bin(_integer) .
How do you write data into a binary file in Python?Write Bytes to File in Python
Example 1: Open a file in binary write mode and then specify the contents to write in the form of bytes. Next, use the write function to write the byte contents to a binary file.
How do you convert a string to binary?The idea is to first calculate the length of the string as n and then run a loop n times. In each iteration store ASCII value of character in variable val and then convert it into binary number and store result in array finally print the array in reverse order.
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