Adding Map Elements to Slice in Sequential Orde - string

Question

I'm working on a text wrapping function. I want it to break a long line of text into string slices of a maximum length of characters. I've got it mostly working. However, sometimes the words are placed out of order.
This happens when there is a long word followed by a short word. I believe the program sees the longer word will not fit on the line so it skips that word and adds in the next word that will fit.
As this is text, the words must stay in the correct order. How can I force the loop to only add words in the correct order?
Actual Output:
[]string{" Go back out of the hotel entrance and your is", " room on lower ground a private street", " entrance."}
Expected Output:
[]string{" Go back out of the hotel entrance and your", " room is on lower ground a private street", " entrance."}
This is what I have so far.
Link: https://play.golang.org/p/YsCWoM9hQJV
package main
import (
"fmt"
"strings"
)
func main() {
directions := "Go back out of the hotel entrance and your room is on the lower ground a private street entrance."
ws := strings.Split(directions, " ")
neededSlices := strings.Count(directions, "") / 48
if strings.Count(directions, "")%48 != 0 {
neededSlices++
}
ls := make([]string, neededSlices, neededSlices)
keys := make(map[string]bool)
for i := 0; i < len(ls); i++ {
for _, v := range ws {
if _, ok := keys[v]; !ok {
if strings.Count(ls[i], "")+strings.Count(v, "") <= 48 {
ls[i] = ls[i] + " " + v
keys[v] = true
}
}
}
}
fmt.Printf("%#v", ls)
}

Answer 1

I think this is simple implementation of what you need
package main
import (
"fmt"
"strings"
)
func main() {
directions := "Go back out of the hotel entrance and your room is on the lower ground a private street entrance."
ws := strings.Split(directions, " ")
sl := []string{""}
i := 0
for _,word := range ws {
if (len(sl[i]) + len(word) + 1) >=48 {
i++
sl = append(sl, "")
}
sl[i] += " " + word
}
fmt.Printf("%#v", sl)
}
Link: https://play.golang.org/p/7R2TS6lv4Tm

Answer 2

The first problem I notice is your usage of a map. A map can only contain a key once. Due to this, your code will only contain each word once in one of the output slices.
The second problem is that you iterate over the whole ws array again for each iteration of the ls slice. I guess you tried to work around this issue with the map?
The solution would be to iterate only once over ws and assign the words to the index in ls.
Also note that strings.Count returns the number of characters (unicode points) in the string plus 1.
Your code btw also adds a space at the beginning of each string in the slice. I am not sure if this is intended (your expected output matches this). In my example solution I deviate from that so my output does not 100% match your stated expected output but I think it gives a more expected result.
package main
import (
"fmt"
"strings"
)
func main() {
directions := "Go back out of the hotel entrance and your hotel room is on the lower ground a private street entrance."
ws := strings.Split(directions, " ")
ls := []string{}
l := 0 // current line length
i := -1
for _, v := range ws {
lv := strings.Count(v, "")-1
if l == 0 || l+lv+1 > 48 {
i++
ls = append(ls, v)
l = lv
continue
}
ls[i] += " " + v
l += lv+1
}
fmt.Printf("%#v", ls)
}
Go Playground: https://play.golang.org/p/HhdX8RudiXn