I am not a pro and I have been scratching my head over understanding what exactly StringIO is used for. I have been looking around the internet for some examples. However, almost all of the examples are very abstract. And they just show "how" to use it. But none of them show "why" and "in which circumstances" one should/will use it? Thanks in advance
p.s. not to be confused with this question on stackoverflow: StringIO Usage which compares string and StringIo.
The StringIO module is an in-memory file-like object. This object can be used as input or output to the most function that would expect a standard file object. When the StringIO object is created it is initialized by passing a string to the constructor. If no string is passed the StringIO will start empty.
Strings are defined as an array of characters. The difference between a character array and a string is the string is terminated with a special character '\0'. Declaration of strings: Declaring a string is as simple as declaring a one-dimensional array. Below is the basic syntax for declaring a string.
The io module provides Python's main facilities for dealing with various types of I/O. There are three main types of I/O: text I/O, binary I/O and raw I/O. These are generic categories, and various backing stores can be used for each of them.
StringIO Module in Python Last Updated : 17 May, 2020 The StringIO module an in-memory file-like object. This object can be used as input or output to the most function that would expect a standard file object.
Since a StringIO object is a file-like object, we can use the file handling operations to read it. A good habit is closing the StringIO object after using it. The StringIO.close () method will help us free the relative memory space. If we operate a closed memory file, a ValueError will be raised.
In cases where you want a file-like object that ACTS like a file, but is writing to an in-memory string buffer: StringIO is the tool. If you're building large strings, such as plain-text documents, and doing a lot of string concatenation, you might find it easier to just use StringIO instead of a bunch of mystr += 'more stuff ' type of operations.
If no string is passed the StringIO will start empty. In both cases, the initial cursor on the file starts at zero. NOTE: This module does not exist in the latest version of Python so to work with this module we have to import it from the io module in Python as io.StringIO.
It's used when you have some API that only takes files, but you need to use a string. For example, to compress a string using the gzip module in Python 2:
import gzip import StringIO stringio = StringIO.StringIO() gzip_file = gzip.GzipFile(fileobj=stringio, mode='w') gzip_file.write('Hello World') gzip_file.close() stringio.getvalue()
StringIO gives you file-like access to strings, so you can use an existing module that deals with a file and change almost nothing and make it work with strings.
For example, say you have a logger that writes things to a file and you want to instead send the log output over the network. You can read the file and write its contents to the network, or you can write the log to a StringIO object and ship it off to its network destination without touching the filesystem. StringIO makes it easy to do it the first way then switch to the second way.
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