EulerPy

EulerPy is a command line tool designed to streamline the process of solving Project Euler problems using Python. The package focuses on two main tasks: firstly, to create Python "template" files with a docstring containing the text of a Project Euler problem for ease-of-reference, and secondly, to check whether a problem has been solved correctly.

Installation

EulerPy can be installed (and updated) from PyPI using pip:

$ pip install --upgrade EulerPy

Conversely, it can be uninstalled using pip as well.

$ pip uninstall EulerPy

Alternatively, OS X users can install EulerPy using Homebrew:

$ brew install euler-py

Usage

First, you'll want to cd to the directory where your Project Euler files are being stored.

$ mkdir ~/project-euler
$ cd ~/project-euler

At this point, you'll probably want to run the euler command, which will prompt to create 001.py, a file containing the text to Project Euler problem #1 as its docstring.

$ euler
No Project Euler files found in the current directory.
Generate file for problem 1? [Y/n]: Y
Successfully created "001.py".

$ cat 001.py
"""
Project Euler Problem 1
=======================

If we list all the natural numbers below 10 that are multiples of 3 or 5,
we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.
"""

At this point, you can open up your editor of choice and code up a solution to the problem, making sure to print() the output. Once you feel that you've solved the problem, run the euler command again to verify your solution is correct. If the answer is correct, the solution will be printed in green and the script will ask to generate the next problem file. If incorrect, the solution will be printed in red instead. Additionally, the time elapsed during the solution-checking process will also be printed.

$ euler
Checking "001.py" against solution: [no output] # (output in red)

$ echo print 42 >> 001.py
$ euler
Checking "001.py" against solution: 42 # (output in green)
Generate file for problem 2? [Y/n]: Y
Successfully created "002.py".

EulerPy also has a few command line options that act as different commands (use euler --help to see a summary of all the options).

--cheat / -c

The --cheat option will print the answer to a problem after prompting the user to ensure that they want to see it. If no problem argument is given, it will print the answer to the problem that they are currently working on.

$ euler --cheat
View answer to problem 2? [y/N]: Y
The answer to problem 2 is <redacted>.

$ euler --cheat 100
View answer to problem 100? [y/N]: Y
The answer to problem 100 is <redacted>.

--generate / -g

The --generate option will create a Python file for the given problem number. If no problem number is given, it will overwrite the most recent problem with a file containing only the problem docstring (after prompting the user).

$ euler --generate
Generate file for problem 2? [Y/n]: Y
"002.py" already exists. Overwrite? [y/N]:
Successfully created "002.py".

$ euler --generate 5
Generate file for problem 5? [Y/n]: n
Aborted!

euler <problem> is equivalent to euler --generate <problem> if the file does not exist.

$ cat 005.py
cat: 005.py: No such file or directory

$ euler 5
Generate file for problem 5? [Y/n]: n
Aborted!

The file generation process will also automatically copy any relevant resource files to a resources subdirectory.

$ euler 22
Generate file for problem 22? [Y/n]: Y
Successfully created "022.py".
Copied "names.txt" to project-euler/resources.

--preview / -p

The --preview option will print the text of a given problem to the terminal; if no problem number is given, it will print the next problem instead.

$ euler --preview
Project Euler Problem 3
The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of the number 600851475143?

$ euler --preview 5
Project Euler Problem 5
2520 is the smallest number that can be divided by each of the numbers
from 1 to 10 without any remainder.

What is the smallest number that is evenly divisible by all of the numbers
from 1 to 20?

--skip / -s

The --skip option will prompt the user to "skip" to the next problem. As of EulerPy v1.1, it will also append a "skipped" suffix to the skipped problem file.

$ euler --skip
Current problem is problem 2.
Generate file for problem 3? [y/N]: Y
Successfully created "003.py".
Renamed "002.py" to "002-skipped.py".

--verify / -v

The --verify option will check whether a given problem file outputs the correct solution to the problem. If no problem number is given, it will check the current problem.

$ euler --verify
Checking "003.py" against solution: [no output] # (output in red)

$ euler --verify 1
Checking "001.py" against solution: <redacted> # (output in green)

As of EulerPy v1.1, verifying a skipped problem file will remove the "skipped" suffix from its filename.

$ euler --verify 2
Checking "002-skipped.py" against solution: <redacted>
Renamed "002-skipped.py" to "002.py".

euler <problem> is equivalent to euler --verify <problem> if the file does exist.

$ cat 001.py
"""
Project Euler Problem 1
=======================

If we list all the natural numbers below 10 that are multiples of 3 or 5,
we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.
"""


$ euler 1
Checking "001.py" against solution: <redacted>

--verify-all

The --verify-all option was added in EulerPy v1.1. It essentially runs --verify on all the problem files it can find in the current directory, but also prints an overview of all of the problems in the directory. Note that if the verification encounters a KeyboardInterrupt exception, it will skip the verification of that specific file. This allows for the ability to skip verifying some files but not others, in the case that some solutions are taking too long to compute.

$ euler --verify-all
Checking "001.py" against solution: <redacted>

Checking "002.py" against solution: ^C

Checking "003.py" against solution: [no output]

---------------------------------------------------------------
C = correct, I = incorrect, E = error, S = skipped, . = missing

Problems 001-020: C S I . .   . . . . .   . . . . .   . . . . .

This option should be run after upgrading to v1.1 from EulerPy v1.0, as it will automatically rename any problems that have been skipped using --skip, making them easy to distinguish from those that have been correctly solved.

File Prefixes

As of v1.3.0, EulerPy will attempt to keep the prefix of problem files consistent. The motivation behind this is that import 001 results in a syntax error whereas import euler001 is valid. By using the latter naming scheme, it is possible to reuse code written in previous files.

$ mv 003.py euler003.py

$ euler --skip
Current problem is problem 3.
Generate file for problem 4? [y/N]: Y
Successfully created "euler004.py".
Renamed "euler003.py" to "euler003-skipped.py".

Contributing

See CONTRIBUTING.rst.

Miscellaneous

The text for the problems in problems.txt were derived from Kyle Keen's Local Euler project, and the solutions in solutions.txt were derived from Bai Li's projecteuler-solutions repository.

See this blog post for insight into the development process.

EulerPy uses Click as a dependency for its CLI functionality.

License

EulerPy is licensed under the MIT License.