String.format() Handbook

1. Quick Summary

String.format() is a static method that returns a formatted string using a specified format string and arguments. It is effectively the sprintf of Java.

• Syntax: String.format(String format, Object... args)

• Key Use: Creating readable output, aligning text in columns, and controlling decimal precision.

• Localization: Use String.format(Locale.US, ...) to ensure consistent formatting (e.g., decimal points vs commas) across different regions.

2. Anatomy of a Specifier

A format specifier follows this structure:%[argument_index$][flags][width][.precision]conversion

• %: Start of specifier.

• flags: formatting options (e.g., - for left-align, 0 for zero-pad).

• width: Minimum number of characters to output.

• precision: Max characters (strings) or decimal places (floats).

• conversion: The type of argument (e.g., s, d, f).

3. Common Converters Cheat Sheet

4. Formatting Flags

5. Width & Precision Examples