user
Definitions

For the purposes of this task, an **isogram** means a string where each character present is used the same number of times and an **n-isogram** means an isogram where each character present is used exactly **n** times.

A **heterogram** means a string in which no character occurs more than once. It follows that a **heterogram** is the same thing as a **1-isogram**.

Examples

*caucasus* is a **2-isogram** because the letters c, a, u and s all occur twice.

*atmospheric* is a **heterogram** because all its letters are used once only.

Task

Using **unixdict.txt** and ignoring capitalization:

**1)** Find and display here all words which are **n-isograms** where **n > 1**.

Present the results as a single list but sorted as follows:

a. By decreasing order of **n**;

b. Then by decreasing order of word length;

c. Then by ascending lexicographic order.
  
  
**2)** Secondly, find and display here all words which are **heterograms** and have more than **10** characters.

Again present the results as a single list but sorted as per b. and c. above.

Reference

* Wikipedia: Heterogram

Other tasks related to string operations:

Metrics

* Array length
* String length
* Copy a string
* Empty string  (assignment)

Counting

* Word frequency
* Letter frequency
* Jewels and stones
* I before E except after C
* Bioinformatics/base count
* Count occurrences of a substring
* Count how many vowels and consonants occur in a string

Remove/replace

* XXXX redacted
* Conjugate a Latin verb
* Remove vowels from a string
* String interpolation (included)
* Strip block comments
* Strip comments from a string
* Strip a set of characters from a string
* Strip whitespace from a string -- top and tail
* Strip control codes and extended characters from a string

Anagrams/Derangements/shuffling

* Word wheel
* ABC problem
* Sattolo cycle
* Knuth shuffle
* Ordered words
* Superpermutation minimisation
* Textonyms (using a phone text pad)
* Anagrams
* Anagrams/Deranged anagrams
* Permutations/Derangements

Find/Search/Determine

* ABC words
* Odd words
* Word ladder
* Semordnilap
* Word search
* Wordiff  (game)
* String matching
* Tea cup rim text
* Alternade words
* Changeable words
* State name puzzle
* String comparison
* Unique characters
* Unique characters in each string
* Extract file extension
* Levenshtein distance
* Palindrome detection
* Common list elements
* Longest common suffix
* Longest common prefix
* Compare a list of strings
* Longest common substring
* Find common directory path
* Words from neighbour ones
* Change e letters to i in words
* Non-continuous subsequences
* Longest common subsequence
* Longest palindromic substrings
* Longest increasing subsequence
* Words containing "the" substring
* Sum of the digits of n is substring of n
* Determine if a string is numeric
* Determine if a string is collapsible
* Determine if a string is squeezable
* Determine if a string has all unique characters
* Determine if a string has all the same characters
* Longest substrings without repeating characters
* Find words which contains all the vowels
* Find words which contain the most consonants
* Find words which contains more than 3 vowels
* Find words whose first and last three letters are equal
* Find words with alternating vowels and consonants

Formatting

* Substring
* Rep-string
* Word wrap
* String case
* Align columns
* Literals/String
* Repeat a string
* Brace expansion
* Brace expansion using ranges
* Reverse a string
* Phrase reversals
* Comma quibbling
* Special characters
* String concatenation
* Substring/Top and tail
* Commatizing numbers
* Reverse words in a string
* Suffixation of decimal numbers
* Long literals, with continuations
* Numerical and alphabetical suffixes
* Abbreviations, easy
* Abbreviations, simple
* Abbreviations, automatic

Song lyrics/poems/Mad Libs/phrases

* Mad Libs
* Magic 8-ball
* 99 bottles of beer
* The Name Game (a song)
* The Old lady swallowed a fly
* The Twelve Days of Christmas

Tokenize

* Text between
* Tokenize a string
* Word break problem
* Tokenize a string with escaping
* Split a character string based on change of character

Sequences

* Show ASCII table
* De Bruijn sequences
* Summarize and say sequence
* Generate lower case ASCII alphabet
assistant
```
my $file = 'unixdict.txt';

my @words = $file.IO.slurp.words.race.map: { $_ => .comb.Bag };

.say for (6...2).map: -> $n {
    next unless my @iso = @words.race.grep({.value.values.all == $n})».key;
    "\n({+@iso}) {$n}-isograms:\n" ~ @iso.sort({[-.chars, ~$_]}).join: "\n";
}

my $minchars = 10;

say "\n({+$_}) heterograms with more than $minchars characters:\n" ~
  .sort({[-.chars, ~$_]}).join: "\n" given
  @words.race.grep({.key.chars >$minchars && .value.values.max == 1})».key;

```

Output:

```
(2) 3-isograms:
aaa
iii

(31) 2-isograms:
beriberi
bilabial
caucasus
couscous
teammate
appall
emmett
hannah
murmur
tartar
testes
anna
coco
dada
deed
dodo
gogo
isis
juju
lulu
mimi
noon
otto
papa
peep
poop
teet
tete
toot
tutu
ii

(32) heterograms with more than 10 characters:
ambidextrous
bluestocking
exclusionary
incomputable
lexicography
loudspeaking
malnourished
atmospheric
blameworthy
centrifugal
christendom
consumptive
countervail
countryside
countrywide
disturbance
documentary
earthmoving
exculpatory
geophysical
inscrutable
misanthrope
problematic
selfadjoint
stenography
sulfonamide
switchblade
switchboard
switzerland
thunderclap
valedictory
voluntarism
```