Summary  
Demonstrates how to apply and customize numeric formats—such as currency, percentage, date, and locale-specific patterns—using built-in and custom format codes.

General domain of usage  
Spreadsheet data presentation

**Number formatting** in Excel helps you present numeric data clearly and professionally by applying currency, percentage, date, and custom formats.

- Format dates according to regional standards via **Home** tab → **Number** group → **Number Format** → **More Number Formats...**, then choose the needed option;
- Change **Currency** via **Home** tab → **Number** group → **Number Format** → **More Number Formats...**;
- Create custom values via **Home** tab → **Number** group → **Number Format** → **More Number Formats...** → **Custom**;
- Alternatively, open **More Number Formats...** using the right-click menu → **Format Cells...**.

Initial Workbook

import unittest
import json
import os
import re


def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)


class TestUserCode(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        cls._no_data = True
        cls.sheet = {}
        cls.styles = {}

        if os.path.exists("payload.json"):
            try:
                with open("payload.json") as f:
                    content = f.read().strip()
                if content:
                    data = json.loads(content)
                    cls.sheet = next(iter(data["sheets"].values()))
                    cls.styles = data.get("styles", {})
                    cls._no_data = False
            except (json.JSONDecodeError, ValueError, StopIteration):
                pass

    # ------------------------------------------------------------------ #
    # Helpers
    # ------------------------------------------------------------------ #

    def _cell(self, row, col):
        row_data = self.sheet.get("cellData", {}).get(str(row), {})
        if str(col) in row_data:
            return row_data[str(col)]
        for key, cell in row_data.items():
            if "-" in key:
                try:
                    start, end = map(int, key.split("-", 1))
                    if start <= col <= end:
                        return cell
                except ValueError:
                    pass
        return None

    def _cell_style(self, row, col):
        cell = self._cell(row, col)
        if not cell:
            return {}
        s = cell.get("s")
        if isinstance(s, str):
            return self.styles.get(s, {})
        if isinstance(s, dict):
            return s
        return {}

    def _number_format(self, row, col):
        return self._cell_style(row, col).get("n", {}).get("pattern", "")

    # ------------------------------------------------------------------ #
    # Step 1 — US date format on A10:A16
    # ------------------------------------------------------------------ #

    @staticmethod
    def _is_us_date_format(fmt):
        stripped = re.sub(r'"[^"]*"', '', fmt)
        match = re.search(r'[mMdDyY]', stripped)
        return match is not None and match.group().lower() == 'm'

    def test_date_format_A10_A16(self):
        if self._no_data:
            _dynamic_test(self, True, "US date format applied to A10:A16.", ""); return
        missing = []
        for row in range(9, 16):
            fmt = self._number_format(row, 0)
            if not self._is_us_date_format(fmt):
                missing.append(f"A{row + 1} (format={fmt!r})")
        _dynamic_test(self, len(missing) == 0,
            "US date format (month-first) applied to A10:A16.",
            f"Expected a US date format (e.g. mm/dd/yyyy) on: {missing}.")

    # ------------------------------------------------------------------ #
    # Step 2 — Dollar ($) currency format on B18:H19
    # ------------------------------------------------------------------ #

    def test_dollar_format_B18_H19(self):
        if self._no_data:
            _dynamic_test(self, True, "Dollar ($) format applied to B18:H19.", ""); return
        missing = []
        for row in range(17, 19):
            for col in range(1, 8):
                fmt = self._number_format(row, col)
                if "$" not in fmt:
                    missing.append(f"{chr(ord('A') + col)}{row + 1} (format={fmt!r})")
        _dynamic_test(self, len(missing) == 0,
            "Dollar ($) format applied to B18:H19.",
            f"Dollar format not found on: {missing}.")

    # ------------------------------------------------------------------ #
    # Step 3 — Custom format 0.00 on B10:H16
    # ------------------------------------------------------------------ #

    def test_custom_format_B10_H16(self):
        if self._no_data:
            _dynamic_test(self, True, "Custom format 0.00 applied to B10:H16.", ""); return
        missing = []
        for row in range(9, 16):
            for col in range(1, 8):
                fmt = self._number_format(row, col)
                if fmt != "0.00":
                    missing.append(f"{chr(ord('A') + col)}{row + 1} (format={fmt!r})")
        _dynamic_test(self, len(missing) == 0,
            "Custom format 0.00 applied to B10:H16.",
            f"Format 0.00 not set on: {missing}.")


if __name__ == "__main__":
    unittest.main()


test_main.py

Dive into the world of Excel with this comprehensive video course, designed to take you from basic navigation to mastering functions and basic data analysis. Starting with foundational skills like data entry and cell formatting, you'll quickly progress to using powerful tools. Whether you're organizing large datasets, performing statistical analysis, or creating dynamic charts, this course equips you with the practical skills needed in today’s data-driven environment.

Kickstart your journey with Excel by understanding its interface, basic functions, and essential data entry techniques. Learn how to navigate toolbars, worksheets, and master the fundamental elements to set a solid foundation.

Dive deeper into Excel by exploring advanced data entry and formatting options. Sharpen your skills in text and number formatting, discover how to effectively use styles, and enhance spreadsheet readability and functionality.

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In this section, you will master advanced Excel formulas and functions, enhancing your ability to manage complex calculations. Learn to display and audit formulas, utilize nested and logical statements, and apply conditions effectively to streamline your data analysis tasks.

Explore comprehensive techniques for sorting, filtering, and managing data efficiently. This section covers everything from basic data organization to advanced filtering and table management, ensuring you can handle and analyze data effectively.

Dive into the art of data visualization using Excel's powerful charting tools. You'll learn to create various types of charts, customize them to enhance visual appeal, and manipulate data within charts to present clear and compelling visual stories.

Gain proficiency in managing worksheets and workbooks within Excel. This section teaches you how to effectively organize and manipulate workbook elements, utilize formatting tools, and secure your work with passwords, providing a thorough grounding in workbook operations.

Number Formatting in Excel

Key Points

Essential Keyboard Shortcuts

Number Formatting in Excel

Key Points

Essential Keyboard Shortcuts