mistaker 0.1.0

A package for emulating common data entry errors

Mistaker

Mistaker is a Python package designed to emulate common data entry errors that occur in real-world datasets. It's particularly useful for testing data quality tools, generating synthetic training data, and simulating typical mistakes found in OCR output, manual transcription, and legacy data migration projects.

Features

• Simulate common transcription and data entry errors for:
  • Text strings and words
  • Personal names and business names
  • Dates in various formats
  • Numeric data
• Configurable error types and rates
• Support for multiple input formats
• Preserves data structure while introducing realistic errors
• Deterministic error generation available for testing

Installation

Install using pip:

pip install mistaker

For development installation:

pip install -e ".[test]"

Quick Start

from mistaker import Word, Name, Date, Number

# Generate word variations
Word.make_mistake("GRATEFUL")   # => "GRATEFU"
Word.make_mistake("GRATEFUL")   # => "GRATAFUL"

# Generate name variations with common mistakes
Name.make_mistake("KIM DEAL")   # => "KIM FEAL"
Name.make_mistake("KIM DEAL")   # => "KIM DEL"
Name("KIM DEAL").chaos()        # => "DEELLL KIN"

# Generate date formatting errors and typos
Date.make_mistake("09/04/1982") # => "1928-09-04"
Date.make_mistake("09/04/1982") # => "0019-82-09"

# Generate numeric transcription errors
Number.make_mistake("12345")    # => "12335"
Number.make_mistake("12345")    # => "72345"

Detailed Usage

Word and Text Errors

from mistaker import Word, ErrorType

# Create a word instance
word = Word("TESTING")

# Generate specific error types
word.mistake(ErrorType.DROPPED_LETTER)  # => "TESTNG"
word.mistake(ErrorType.DOUBLE_LETTER)   # => "TESSTING"
word.mistake(ErrorType.MISREAD_LETTER)  # => "TEZTING"
word.mistake(ErrorType.MISTYPED_LETTER) # => "TEDTING"
word.mistake(ErrorType.EXTRA_LETTER)    # => "TESTINGS"
word.mistake(ErrorType.MISHEARD_LETTER) # => "TEZDING"

Name Handling

from mistaker import Name

# Create a name instance
name = Name("Robert James Smith")

# Generate name variations
variations = name.get_name_variations()
# Returns variations like:
# - "Smith, Robert"
# - "R James Smith"
# - "Robert Smith"
# - "Smith Robert"

# Generate case variants
cases = name.get_case_variants()
# Returns:
# - "Robert James Smith"
# - "ROBERT JAMES SMITH"
# - "robert james smith"

# Generate multiple errors
name.chaos()  # Applies 1-6 random errors
# John Smith -> JAHN SMEH

Date Handling

from mistaker import Date

# Create a date instance
date = Date("2023-05-15")

# Supports multiple input formats
date = Date("05/15/2023")  # US format
date = Date("15/05/2023")  # UK format

# Generate specific error types
date.mistake(ErrorType.MONTH_DAY_SWAP)    # => "2023-15-05"
date.mistake(ErrorType.ONE_DECADE_DOWN)   # => "2013-05-15"
date.mistake(ErrorType.Y2K)               # => "0023-05-15"

Number Handling

from mistaker import Number

# Create a number instance
number = Number("12345")

# Generate specific error types
number.mistake(ErrorType.ONE_DIGIT_UP)     # => "12346"
number.mistake(ErrorType.ONE_DIGIT_DOWN)   # => "12344"
number.mistake(ErrorType.KEY_SWAP)         # => "21345"
number.mistake(ErrorType.DIGIT_SHIFT)      # => "01234"
number.mistake(ErrorType.MISREAD)          # => "12375"
number.mistake(ErrorType.NUMERIC_KEY_PAD)  # => "12348"

Error Types

Text and Name Errors

• Dropped Letters: Missing characters (e.g., "testing" → "testng")
• Double Letters: Repeated characters (e.g., "testing" → "tessting")
• Misread Letters: Similar-looking character substitutions (e.g., "testing" → "tezting")
• Mistyped Letters: Keyboard proximity errors (e.g., "testing" → "tedting")
• Extra Letters: Common suffix additions (e.g., "test" → "tests")
• Misheard Letters: Phonetic errors (e.g., "testing" → "tesding")

Number Errors

• Single Digit Errors: Off-by-one errors
• Key Swaps: Adjacent digit transposition
• Digit Shifts: Decimal/position shifts
• Misread Numbers: Similar-looking number substitution
• Numeric Keypad Errors: Based on number pad layout

Date Errors

• Month/Day Swaps: Common in international formats
• Decade Shifts: Common in manual entry
• Y2K Issues: Two-digit year ambiguity
• All Number-Based Errors: Inherited from number handling

Development

Running Tests

pytest

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Inspired by real-world data quality challenges in government and enterprise systems
• Error patterns based on extensive analysis of common transcription mistakes
• Designed to support data quality testing and synthetic data generation