freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/rosetta-code/align-columns.english.md

7.1 KiB

title id challengeType
Align columns 594810f028c0303b75339ad0 5

Description

Given a text file of many lines, where fields within a line are delineated by a single $ character, write a program that aligns each column of fields by ensuring that words in each column are separated by at least one space. Further, allow for each word in a column to be either left justified, right justified, or center justified within its column.

Use the following text to test your programs:

Given$a$text$file$of$many$lines
where$fields$within$a$line$
are$delineated$by$a$single$'dollar'$character
write$a$program
that$aligns$each$column$of$fields
by$ensuring$that$words$in$each$
column$are$separated$by$at$least$one$space.
Further,$allow$for$each$word$in$a$column$to$be$either$left$
justified,$right$justified
or$center$justified$within$its$column.

Note that:

The example input texts lines may, or may not, have trailing dollar characters. All columns should share the same alignment. Consecutive space characters produced adjacent to the end of lines are insignificant for the purposes of the task. Output text will be viewed in a mono-spaced font on a plain text editor or basic terminal. The minimum space between columns should be computed from the text and not hard-coded. It is not a requirement to add separating characters between or around columns.

Instructions

Tests

tests:
  - text: <code>formatText</code> is a function.
    testString: assert(typeof formatText === 'function', '<code>formatText</code> is a function.');
  - text: '<code>formatText</code> with the above input and "right" justification should produce the following: '
    testString: 'assert.strictEqual(formatText(testInput, ''right''), rightAligned, ''<code>formatText</code> with the above input and "right" justification should produce the following: '');'
  - text: '<code>formatText</code> with the above input and "left" justification should produce the following: '
    testString: 'assert.strictEqual(formatText(testInput, ''left''), leftAligned, ''<code>formatText</code> with the above input and "left" justification should produce the following: '');'
  - text: '<code>formatText</code> with the above input and "center" justification should produce the following: '
    testString: 'assert.strictEqual(formatText(testInput, ''center''), centerAligned, ''<code>formatText</code> with the above input and "center" justification should produce the following: '');'

Challenge Seed

const testArr = [
  'Given$a$text$file$of$many$lines',
  'where$fields$within$a$line$',
  'are$delineated$by$a$single$"dollar"$character',
  'write$a$program',
  'that$aligns$each$column$of$fields$',
  'by$ensuring$that$words$in$each$',
  'column$are$separated$by$at$least$one$space.',
  'Further,$allow$for$each$word$in$a$column$to$be$either$left$',
  'justified,$right$justified',
  'or$center$justified$within$its$column.'
];

function formatText (input, justification) {
  // Good luck!
}

After Test

const testInput = [
  'Given$a$text$file$of$many$lines',
  'where$fields$within$a$line$',
  'are$delineated$by$a$single$\"dollar\"$character',
  'write$a$program',
  'that$aligns$each$column$of$fields$',
  'by$ensuring$that$words$in$each$',
  'column$are$separated$by$at$least$one$space.',
  'Further,$allow$for$each$word$in$a$column$to$be$either$left$',
  'justified,$right$justified',
  'or$center$justified$within$its$column.'
];

const rightAligned = '     Given          a      text   file     of     many     lines\n' +
'     where     fields    within      a   line \n' +
'       are delineated        by      a single "dollar" character\n' +
'     write          a   program\n' +
'      that     aligns      each column     of   fields \n' +
'        by   ensuring      that  words     in     each \n' +
'    column        are separated     by     at    least       one space.\n' +
'  Further,      allow       for   each   word       in         a column to be either left \n' +
'justified,      right justified\n' +
'        or     center justified within    its  column.';

const leftAligned = 'Given      a          text      file   of     many     lines    \n' +
'where      fields     within    a      line   \n' +
'are        delineated by        a      single "dollar" character\n' +
'write      a          program  \n' +
'that       aligns     each      column of     fields   \n' +
'by         ensuring   that      words  in     each     \n' +
'column     are        separated by     at     least    one       space.\n' +
'Further,   allow      for       each   word   in       a         column to be either left \n' +
'justified, right      justified\n' +
'or         center     justified within its    column. ';

const centerAligned = '  Given        a        text     file    of     many     lines  \n' +
'  where      fields    within     a     line  \n' +
'   are     delineated    by       a    single \"dollar\" character\n' +
'  write        a       program \n' +
'   that      aligns     each    column   of    fields  \n' +
'    by      ensuring    that    words    in     each   \n' +
'  column      are     separated   by     at    least      one    space.\n' +
' Further,    allow       for     each   word     in        a     column to be either left \n' +
'justified,   right    justified\n' +
'    or       center   justified within  its   column. ';

Solution

const testArr = [
  'Given$a$text$file$of$many$lines',
  'where$fields$within$a$line$',
  'are$delineated$by$a$single$"dollar"$character',
  'write$a$program',
  'that$aligns$each$column$of$fields$',
  'by$ensuring$that$words$in$each$',
  'column$are$separated$by$at$least$one$space.',
  'Further,$allow$for$each$word$in$a$column$to$be$either$left$',
  'justified,$right$justified',
  'or$center$justified$within$its$column.'
];

String.prototype.repeat = function (n) { return new Array(1 + parseInt(n)).join(this); };

function formatText (input, justification) {
  let x, y, max, cols = 0, diff, left, right;
  for (x = 0; x < input.length; x++) {
    input[x] = input[x].split('$');
    if (input[x].length > cols) {
      cols = input[x].length;
    }
  }
  for (x = 0; x < cols; x++) {
    max = 0;
    for (y = 0; y < input.length; y++) {
      if (input[y][x] && max < input[y][x].length) {
        max = input[y][x].length;
      }
    }
    for (y = 0; y < input.length; y++) {
      if (input[y][x]) {
        diff = (max - input[y][x].length) / 2;
        left = ' '.repeat(Math.floor(diff));
        right = ' '.repeat(Math.ceil(diff));
        if (justification === 'left') {
          right += left; left = '';
        }
        if (justification === 'right') {
          left += right; right = '';
        }
        input[y][x] = left + input[y][x] + right;
      }
    }
  }
  for (x = 0; x < input.length; x++) {
    input[x] = input[x].join(' ');
  }
  input = input.join('\n');
  return input;
}