Formatting Cheat Sheet

Number Formatting

1. Fixed Decimal Format (f):

   • Example: Formatting 12345.6789 to two decimal places.

   • D3 Format: d3.format(".2f")

   • Output: "12345.68"

2. Percentage Format (%):

   • Example: Formatting 0.123 as a percentage.

   • D3 Format: d3.format(".1%")

   • Output: "12.3%"

3. Scientific Notation (e):

   • Example: Formatting 12345 in scientific notation.

   • D3 Format: d3.format(".2e")

   • Output: "1.23e+4"

4. SI Prefix with Significant Digits (s):

   • Example: Formatting 12345 with SI prefix.

   • D3 Format: d3.format(".3s")

   • Output: "12.3k"

5. Rounded (r):

   • Example: Rounding 12345.6789.

   • D3 Format: d3.format(".4r")

   • Output: "12350"

6. Comma Separated (,):

   • Example: Formatting 12345.6789 with comma separation.

   • D3 Format: d3.format(",.2f")

   • Output: "12,345.68"

7. Currency ($):

   • Example: Formatting 12345.67 as currency.

   • D3 Format: d3.format("$,.2f")

   • Output: "$12,345.67"

8. Binary (b):

   • Example: Formatting 10 in binary.

   • D3 Format: d3.format("b")

   • Output: "1010"

9. Hexadecimal (x or X):

   • Example: Formatting 255 in hexadecimal.

   • D3 Format: d3.format("x")

   • Output: "ff"

10. Zero Padding (0):

    • Example: Formatting 5 as a two-digit number.

    • D3 Format: d3.format("02d")

    • Output: "05"

These examples show how D3.js can format numbers in many ways, including fixed decimals, percentages, scientific notation, and more. The format specifiers (like .2f, .1%, .3s) determine the precise formatting method.

For more detailed information and examples, you can refer to the D3.js Format API Reference.

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Time Formatting

1. Abbreviated Weekday Name (%a):

   • Example: Formatting a date to show the abbreviated weekday.

   • D3 Format: d3.timeFormat("%a")

   • Output for a Sunday: "Sun"

2. Full Weekday Name (%A):

   • Example: Formatting a date to show the full weekday name.

   • D3 Format: d3.timeFormat("%A")

   • Output for a Sunday: "Sunday"

3. Abbreviated Month Name (%b):

   • Example: Formatting a date to show the abbreviated month name.

   • D3 Format: d3.timeFormat("%b")

   • Output for January: "Jan"

4. Full Month Name (%B):

   • Example: Formatting a date to show the full month name.

   • D3 Format: d3.timeFormat("%B")

   • Output for January: "January"

5. Zero-Padded Day of the Month (%d):

   • Example: Formatting a date to show the day of the month with zero padding.

   • D3 Format: d3.timeFormat("%d")

   • Output for the 5th of the month: "05"

6. 24-Hour Clock Hour (%H):

   • Example: Formatting a time to show the hour in 24-hour format.

   • D3 Format: d3.timeFormat("%H")

   • Output for 3 PM: "15"

7. 12-Hour Clock Hour (%I):

   • Example: Formatting a time to show the hour in 12-hour format.

   • D3 Format: d3.timeFormat("%I")

   • Output for 15:00 (3 PM): "03"

8. Month as Decimal Number (%m):

   • Example: Formatting a date to show the month as a decimal number.

   • D3 Format: d3.timeFormat("%m")

   • Output for January: "01"

9. Minute as Decimal Number (%M):

   • Example: Formatting a time to show the minute.

   • D3 Format: d3.timeFormat("%M")

   • Output for 07 minutes past: "07"

10. AM or PM (%p):

    • Example: Formatting a time to indicate AM or PM.

    • D3 Format: d3.timeFormat("%p")

    • Output for 3 PM: "PM"

11. Second as Decimal Number (%S):

    • Example: Formatting a time to show the second.

    • D3 Format: d3.timeFormat("%S")

    • Output for 09 seconds past: "09"

12. Year without Century (%y):

    • Example: Formatting a date to show the year without the century.

    • D3 Format: d3.timeFormat("%y")

    • Output for 2024: "24"

13. Year with Century (%Y):

    • Example: Formatting a date to show the full year.

    • D3 Format: d3.timeFormat("%Y")

    • Output for 2024: "2024"

These examples demonstrate how to format dates and times in D3.js using different directives. By combining these directives, you can create custom formats for any date or time value. For more detailed information and examples, refer to the D3.js Time Format API Reference.