How I found a good opener for Wordle

Like some other people, I played Wordle the last days. Today, I wrote a little tool to find out whats can be a good opener. Jotto is a similar game so it’s easy to find a list of words like this https://www.easysurf.cc/list1.htm

I downloaded and checked it against my helper tool. The code is not a beauty but it works (and I hope correctly)

package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
)

func main() {
	checkAgainstWordlist()
}

func checkAgainstWordlist() {
	lettercount := make(map[string]int)

	file, err := os.Open("Wordlist")
	if err != nil {
		panic(err)
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {

		for _, letter := range scanner.Text() {
			if val, ok := lettercount[rune2c(letter)]; ok {
				lettercount[rune2c(letter)] = val + 1
			} else {
				lettercount[rune2c(letter)] = 1
			}
		}
	}
	fmt.Println(rankByWordCount(lettercount))

	if err := scanner.Err(); err != nil {
		panic(err)
	}
}

func rune2c(r rune) string {
	return fmt.Sprintf("%c", r)
}

// https://stackoverflow.com/questions/18695346/how-can-i-sort-a-mapstringint-by-its-values
func rankByWordCount(wordFrequencies map[string]int) PairList {
	pl := make(PairList, len(wordFrequencies))
	i := 0
	for k, v := range wordFrequencies {
		pl[i] = Pair{k, v}
		i++
	}
	sort.Sort(sort.Reverse(pl))
	return pl
}

type Pair struct {
	Key   string
	Value int
}

type PairList []Pair

func (p PairList) Len() int {
	return len(p)
}

func (p PairList) Less(i, j int) bool {
	return p[i].Value < p[j].Value
}

func (p PairList) Swap(i, j int) {
	p[i], p[j] = p[j], p[i]
}

The result was

[{e 709} {a 679} {r 565} {t 499} {i 480} {o 457} {s 429} {l 428} {n 418} {c 352} {u 335} {h 302} {d 258} {p 240} {y 238} {m 222} {g 203} {b 185} {k 154} {w 137} {f 137} {v 99} {x 30} {q 26} {z 24} {j 19}]

(e = 709 times, a = 679 times, …)

That means e,a,r,t, and i are the most used letters in the list. A word for this combination of letters can be IRATE.

Update 14.01.2022

I got the Wordlist from Wordle itself and run my code again. The result are:

[{s 6665} {e 6662} {a 5990} {o 4438} {r 4158} {i 3759} {l 3371} {t 3295} {n 2952} {u 2511} {d 2453} {y 2074} {c 2028} {p 2019} {m 1976} {h 1760} {g 1644} {b 1627} {k 1505} {f 1115} {w 1039} {v 694} {z 434} {j 291} {x 288} {q 112}]

That meas a possible good opener can be AROSE.

Update 15.01.2022

Someone told me that Wordle are using two list. The first list for the Wordle itself and the second list for possible words. I made the mistake and combined both lists in the last result.

I tried it again with the list for the game and the result is slightly different:

[{e 1233} {a 979} {r 899} {o 754} {t 729} {l 719} {i 671} {s 669} {n 575} {c 477} {u 467} {y 425} {d 393} {h 389} {p 367} {m 316} {g 311} {b 281} {f 230} {k 210} {w 195} {v 153} {z 40} {x 37} {q 29} {j 27}]

e,a,r,o, and t are the most used letters. I don’t know a word with this letters so I think I will stay with AROSE as an opener.