This article discusses how to check if a generator is empty in Python.
Check if the Generator Is Empty in Python
Checking if a generator is empty in Python refers to a path getting checked to ensure that it is empty. For this, the relevant path must be identified beforehand as either a directory or a file, which allows us to select the required approach to check to be used effortlessly.
The following snippet shows the involvement of two placeholder variables named
dirpath. These variables are used for the identification of a local file and directory:
dirpath = "/mnt/f/code.books/articles/python" filepath = "/mnt/f/code.books/articles/python/code/file_dir.py"
The above placeholder variables can work with the
os module in Python that acts as a standard package. It can be used with objects, functions, and constants that work with the relevant operating system.
os module can also be denoted as
os.path and involves
isfile() that work as functions. These functions enable the users to differentiate between the given directory and any file.
The return value in the working of both functions is a Boolean value.
Consider the following example:
import os dirpath = "/mnt/f/code.books/articles/python" filepath = "/mnt/f/code.books/articles/python/code/file_dir.py" os.path.isfile (dirpath) # False os.path.isdir (dirpath) # True os.path.isfile (filepath) # True os.path.isdir (filepath) # False
isfile() functions are denoted as
os.path.isfile, respectively, in this example. The return value in the working of both functions is a Boolean value.
It means that the output of the implementation of these functions should return as either
False. The return values of
False show if the relevant path is either a file or directory based on its respective function.
After this confirmation, another module named
pathlib can be used in and after the Python 3.4 version. With this module, an object-oriented interface has enabled users to work with their file systems easily.
This module ensures simplifications within the implementation compared to the
os.path module. It has a
Path class involved in its work, with a path accepted as an argument.
After this, a
Path object is returned by that path so the users can easily chain or query it with attributes and methods.
Take a look at the following code snippet:
from pathlib import Path dirpath = "/mnt/f/code.books/articles/python" filepath = "/mnt/f/code.books/articles/python/code/file_dir.py" Path (dirpath).is_file() # False Path (dirpath).is_dir() # True Path (filepath).is_file() # True Path (dirpath).is_file() # False
In this snippet, the
Path object is checked to ensure that it is either a directory or a file with a Boolean value as the return value. The
filepath variables are also involved with the
Path object associated with the
Their implementation will return output as either
False, showing either a directory or a file as the object.
The next step is to check if a generator is empty and can involve an empty path or file. The path or file can also be named a zero-byte file and can be of different types with no content or data.
Remember that files containing metadata with no data do not fall under the umbrella of empty files. This can even involve music files that contain an author.
Empty files can be easily created on platforms like macOS and LINUX. Here is a snippet of how that can be done:
$ touch emptyfile
The following snippet shows how to do that on Windows:
$ type nul > emptyfile
After doing this, we have to define variables with which a non-empty file or an empty file can point to an empty file. That empty file is likely zero bytes, whereas the non-empty file is a byte in size.
The following is an example of what that can look like:
emptyfile = "/mnt/f/code.books/articles/python/emptyfile" nonemptyfile = "/mnt/f/code.books/articles/python/onebytefile”
With this, an optional parameter can be used for the
next() function, with which users can ensure that the generator is empty.
Here is a code snippet for that:
_exhausted = object() if next (some_generator, _exhausted) is _exhausted: print ('empty generator')
In this snippet, the empty generator is denoted by an exhausted iterator and an object’s usage. After this, an
if condition is placed within the implementation, which checks for an exhausted generator with some generator value.
In the case of an empty generator, the condition is fulfilled, and the implementation returns an empty generator as its output.
- Send Function in Python Generators
- Python Generator Comprehension
- Differentiate Iterator and Generator in Python