For context, this problem is based on a old chat-bot project I did.
Problem:
Given a string of words containing any of the characters:
" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~"
Find the frequency of each triplet of words. All non-alphanumeric characters should be ignored, and input/output will be case-insensitive.
For this challenge, the "triplets" of a phrase are each consecutive chunk of 3 words along the string.
For example, in the string
"Oh hi there guy. What's up? Oh hi there."
The "triplets" of the string are
[["oh", "hi", "there"], ["hi", "there", "guy"], ["there", "guy", "whats"], ["guy", "whats", "up"],
["whats", "up", "oh"], ["up", "oh", "hi"], ["oh", "hi", "there"]]
The frequency of each triplet is 1, except for ["oh", "hi", "there"], which appears twice.
Input
Input will be a string of space-delimited "words" that may contain any of the characters mentioned above. Although punctuation is to be ignored, it must be handled.
You can assume the input will always contain at least 3 words, and that there won't be consecutive whitespace.
Output
Output can be anything that shows the frequency of each triplet.
For the string "Oh hi there guy.", possible outputs could be:
{"oh hi there":1, "hi there guy":1}
["oh hi there", 1, "hi there guy", 1]
"oh hi there|1 hi there guy|1"
^ Or any other delimiter
Test Cases (Output order doesn't matter):
"Oh hi there guy. What's up? Oh hi there."
{["oh" "hi" "there"] 2,
["hi" "there" "guy"] 1,
["there" "guy" "whats"] 1,
["guy" "whats" "up"] 1,
["whats" "up" "oh"] 1,
["up" "oh" "hi"] 1}
"aa aa aa aa"
{["aa" "aa" "aa"] 2}
"aa bb a bb a bb a cc a bb a"
{["aa" "bb" "a"] 1,
["bb" "a" "bb"] 2,
["a" "bb" "a"] 3,
["bb" "a" "cc"] 1,
["a" "cc" "a"] 1,
["cc" "a" "bb"] 1}
"99 bottles of beer"
{["99" "bottles" "of"] 1,
["bottles" "of" "beer"] 1}
"There are two main types of chatbots, one functions based on a set of rules, and the other more advanced version uses artificial intelligence. The chatbots based on rules, tend to be limited in functionality, and are as smart as they are programmed to be. On the other end, a chatbot that uses artificial intelligence, understands language, not just commands, and continuously gets smarter as it learns from conversations it has with people."
{["main" "types" "of"] 1,
["rules" "and" "the"] 1,
["of" "chatbots" "one"] 1,
["to" "be" "limited"] 1,
["artificial" "intelligence" "understands"] 1,
["it" "has" "with"] 1,
["chatbots" "based" "on"] 1,
["smarter" "as" "it"] 1,
["the" "chatbots" "based"] 1,
["other" "more" "advanced"] 1,
["commands" "and" "continuously"] 1,
["chatbots" "one" "functions"] 1,
["tend" "to" "be"] 1,
["a" "chatbot" "that"] 1,
["continuously" "gets" "smarter"] 1,
["advanced" "version" "uses"] 1,
["functionality" "and" "are"] 1,
["are" "two" "main"] 1,
["based" "on" "rules"] 1,
["on" "a" "set"] 1,
["there" "are" "two"] 1,
["the" "other" "more"] 1,
["just" "commands" "and"] 1,
["the" "other" "end"] 1,
["that" "uses" "artificial"] 1,
["based" "on" "a"] 1,
["limited" "in" "functionality"] 1,
["smart" "as" "they"] 1,
["are" "as" "smart"] 1,
["from" "conversations" "it"] 1,
["other" "end" "a"] 1,
["intelligence" "the" "chatbots"] 1,
["functions" "based" "on"] 1,
["in" "functionality" "and"] 1,
["intelligence" "understands" "language"] 1,
["chatbot" "that" "uses"] 1,
["more" "advanced" "version"] 1,
["gets" "smarter" "as"] 1,
["rules" "tend" "to"] 1,
["on" "rules" "tend"] 1,
["as" "it" "learns"] 1,
["are" "programmed" "to"] 1,
["and" "the" "other"] 1,
["understands" "language" "not"] 1,
["and" "are" "as"] 1,
["of" "rules" "and"] 1,
["has" "with" "people"] 1,
["end" "a" "chatbot"] 1,
["set" "of" "rules"] 1,
["and" "continuously" "gets"] 1,
["as" "they" "are"] 1,
["they" "are" "programmed"] 1,
["as" "smart" "as"] 1,
["two" "main" "types"] 1,
["a" "set" "of"] 1,
["uses" "artificial" "intelligence"] 2, # <----- 2 Here
["it" "learns" "from"] 1,
["be" "limited" "in"] 1,
["programmed" "to" "be"] 1,
["types" "of" "chatbots"] 1,
["conversations" "it" "has"] 1,
["one" "functions" "based"] 1,
["be" "on" "the"] 1,
["not" "just" "commands"] 1,
["version" "uses" "artificial"] 1,
["learns" "from" "conversations"] 1,
["artificial" "intelligence" "the"] 1,
["to" "be" "on"] 1,
["on" "the" "other"] 1,
["language" "not" "just"] 1}
Your submission can be a function or full program, and can take input via stdin, or as an argument. It may output by returning, or printing to the stdout.
This is code golf, so the shortest number of bytes wins.
"spam eggs ham"(with double spaces, which markdown removes) as["spam", "", "eggs", "", "ham"]and at least one as["spam", "eggs", "ham"]) \$\endgroup\$