format 1.0.0-nullsafety.0

Formatting library for Dart.

Formatting library for Dart

The format string syntax is almost similar to the one used by format in Python.

Usage

A simple usage example:

import 'package:format/format.dart';
import 'package:intl/intl.dart';

void main() {
  print('hello {}'.format(['world'])); // hello world
  print('{} {}'.format(['hello', 'world'])); // hello world
  print('{1} {0}'.format(['hello', 'world'])); // world hello
  print('{} {} {0} {}'.format(['hello', 'world'])); // hello world hello world
  print('{a} {b}'.format([], {'a': 'hello', 'b': 'world'})); // hello world

  print(format('{a} {"a"} {"+"} {"hello world"}', [], {'a': 1, '+': 2, 'hello world': 3})); // 1 1 2 3
  print(format("{a} {'a'} {'+'} {'hello world'}", [], {'a': 1, '+': 2, 'hello world': 3})); // 1 1 2 3

  const n = 123.4567;
  print(format('{:.2f}', [n])); // 123.46

  print(format('{:10.2f}', [n])); // '    123.46'
  print(format('{:<10.2f}', [n])); // '123.46    '
  print(format('{:^10.2f}', [n])); // '  123.46  '
  print(format('{:>10.2f}', [n])); // '    123.46'

  print(format('{:*<10.2f}', [n])); // 123.46****
  print(format('{:*^10.2f}', [n])); // **123.46**
  print(format('{:*>10.2f}', [n])); // ****123.46

  print(format('{:010.2f}', [n])); // 0000123.46
  print(format('{:012,.2f}', [n])); // 0,000,123.46
  print(format('{:012_.2f}', [n])); // 0_000_123.46

  print(format('{:0{},.{}f}', [n, 12, 2])); // 0,000,123.46
  print(format('{value:0{width},.{precision}f}', [], {'value': n, 'width': 12, 'precision': 2})); // 0,000,123.46

  const n1 = 123456.789;
  const n2 = 1234567.89;
  print(format('{:g}', [n1])); // 123457
  print(format('{:g}', [n2])); // 1.23457e+6
  print(format('{:.9g}', [n1])); // 123456.789
  print(format('{:.9g}', [n2])); // 1234567.89
  print(format('{:.5g}', [n1])); // 1.2346e+5
  print(format('{:.5g}', [n2])); // 1.2346e+6

  print(format('{:g}', [double.nan])); // nan
  print(format('{:g}', [double.infinity])); // inf
  print(format('{:g}', [double.negativeInfinity])); // -inf

  const i = 12345678;
  print(format('{:b}', [i])); // 101111000110000101001110
  print(format('{:d}', [i])); // 12345678
  print(format('{:x}', [i])); // bc614e
  print(format('{:X}', [i])); // BC614E
  print(format('{:#x}', [i])); // 0xbc614e
  print(format('{:#X}', [i])); // 0xBC614E

  print(format('{:_b}', [i])); // 1011_1100_0110_0001_0100_1110
  print(format('{:,d}', [i])); // 12,345,678
  print(format('{:_d}', [i])); // 12_345_678
  print(format('{:_x}', [i])); // bc_614e
  print(format('{:_X}', [i])); // BC_614E
  print(format('{:#_x}', [i])); // 0xbc_614e
  print(format('{:#_X}', [i])); // 0xBC_614E

  print(format('{:c}+{:c}+{:c}+{:c}={:c}', [
    0x1F468, // 👨
    0x1F469, // 👩
    0x1F466, // 👦
    0x1F467, // 👧
    [0x1F468, 0x200D, 0x1F469, 0x200D, 0x1F466, 0x200D, 0x1F467], // 👨‍👩‍👦‍👧
  ]));

  const m = 12345678.9;
  Intl.defaultLocale = 'ru_RU';
  print(format('{:n}', [m])); // 1,23457E7
  print(format('{:.9n}', [m])); // 12345678,9
  print(format('{:012,.9n}', [m])); // 12 345 678,9
  print(format('{:n}', [double.nan])); // не число
  print(format('{:n}', [double.infinity])); // ∞
  print(format('{:n}', [double.negativeInfinity])); // -∞

  Intl.defaultLocale = 'de_DE';
  print(format('{:n}', [m])); // 1,23457E7
  print(format('{:.9n}', [m])); // 12345678,9
  print(format('{:012,.9n}', [m])); // 12.345.678,9

  Intl.defaultLocale = 'en_IN';
  print(format('{:n}', [m])); // 1.23457E7
  print(format('{:.9n}', [m])); // 12345678.9
  print(format('{:012,.9n}', [m])); // 1,23,45,678.9

  Intl.defaultLocale = 'bn';
  print(format('{:n}', [m])); // ১.২৩৪৫৭E৭
  print(format('{:.9n}', [m])); // ১২৩৪৫৬৭৮.৯
  print(format('{:012,.9n}', [m])); // ১,২৩,৪৫,৬৭৮.৯

  Intl.defaultLocale = 'ar_EG';
  print(format('{:n}', [m])); // ١٫٢٣٤٥٧اس٧
  print(format('{:.9n}', [m])); // ١٢٣٤٥٦٧٨٫٩
  print(format('{:012,.9n}', [m])); // ١٢٬٣٤٥٬٦٧٨٫٩
  print(format('{:n}', [double.nan])); // ليس رقم
}