Count Letters

count-letters is a simple Python package for counting characters that appear only once in a text.

The package can be used from the command line or directly in Python code.

Features

• Count unique characters in a string
• Read text from a UTF-8 file
• Use the package from the command line
• Use the package in Python code
• Supports Python 3.10 and newer

Requirements

• Python 3.10 or newer

Installation

Install the package from PyPI:

pip install count-letters

Command Line Usage

After installation, the count-letters command is available.

Count characters in a string

count-letters --string "hello"

Short version:

count-letters -s "hello"

Output:

3

The characters h, e, and o appear only once, so the result is 3.

Count characters from a file

Create a UTF-8 text file, for example text.txt:

hello

Run:

count-letters --file text.txt

or:

count-letters -f text.txt

Output:

3

Using both arguments

If --file and --string are used together, --file has priority.

count-letters --string "error" --file text.txt

In this case, the program reads and processes the content of text.txt.

File errors

If the specified file does not exist, the program shows an error message:

count-letters --file missing.txt

error: Файл не знайдено

Using as a Python Package

You can also use the package directly in Python code:

from count_letters.collection import count_unique_letters

result = count_unique_letters("hello")
print(result)

Output:

3

To read text from a file:

from count_letters.collection import open_and_read_file

text = open_and_read_file("text.txt")
print(text)

Help

To see all available command-line options:

count-letters --help

Development

Install the project and development dependencies:

uv sync

Run tests:

uv run pytest

Run code checks:

uv run ruff check .
uv run ruff format --check .
uv run mypy count_letters tests

Build

Build the package with:

uv build

The built package files will be created in the dist directory.