Split 2 numbers character into it's own new line - r

Question

I've a character object with 84 elements.
> head(output.by.line)
[1] "\n17"
[2] "Now when Joseph saw that his father"
[3] "laid his right hand on the head of"
[4] "Ephraim, it displeased him; so he took"
[5] "hold of his father's hand to remove it"
[6] "from Ephraim's head to Manasseh's"
But there is a line that has 2 numbers (49) that is not in it's own line:
[35] "49And Jacob called his sons and"
I'd like to transform this into:
[35] "\n49"
[36] "And Jacob called his sons and"
And insert this in the correct numeration, after object 34.
Dput Output:
dput(output.by.line)
c("\n17", "Now when Joseph saw that his father", "laid his right hand on the head of",
"Ephraim, it displeased him; so he took", "hold of his father's hand to remove it",
"from Ephraim's head to Manasseh's", "head.", "\n18", "And Joseph said to his father, \"Not so,",
"my father, for this one is the firstborn;", "put your right hand on his head.\"",
"\n19", "But his father refused and said, \"I", "know, my son, I know. He also shall",
"become a people, and he also shall be", "great; but truly his younger brother shall",
"be greater than he, and his descendants", "shall become a multitude of nations.\"",
"\n20", "So he blessed them that day, saying,", "\"By you Israel will bless, saying, \"May",
"God make you as Ephraim and as", "Manasseh!\"' And thus he set Ephraim",
"before Manasseh.", "\n21", "Then Israel said to Joseph, \"Behold, I",
"am dying, but God will be with you and", "bring you back to the land of your",
"fathers.", "\n22", "Moreover I have given to you one", "portion above your brothers, which I",
"took from the hand of the Amorite with", "my sword and my bow.\"",
"49And Jacob called his sons and", "said, \"Gather together, that I may tell",
"you what shall befall you in the last", "days:", "\n2", "\"Gather together and hear, you sons of",
"Jacob, And listen to Israel your father.", "\n3", "\"Reuben, you are my firstborn, My",
"might and the beginning of my strength,", "The excellency of dignity and the",
"excellency of power.", "\n4", "Unstable as water, you shall not excel,",
"Because you went up to your father's", "bed; Then you defiled it-- He went up to",
"my couch.", "\n5", "\"Simeon and Levi are brothers;", "Instruments of cruelty are in their",
"dwelling place.", "\n6", "Let not my soul enter their council; Let",
"not my honor be united to their", "assembly; For in their anger they slew a",
"man, And in their self-will they", "hamstrung an ox.", "\n7",
"Cursed be their anger, for it is fierce;", "And their wrath, for it is cruel! I will",
"divide them in Jacob And scatter them", "in Israel.", "\n8",
"\"Judah, you are he whom your brothers", "shall praise; Your hand shall be on the",
"neck of your enemies; Your father's", "children shall bow down before you.",
"\n9", "Judah is a lion's whelp; From the prey,", "my son, you have gone up. He bows",
"down, he lies down as a lion; And as a", "lion, who shall rouse him?",
"\n10", "The scepter shall not depart from", "Judah, Nor a lawgiver from between his",
"feet, Until Shiloh comes; And to Him", "shall be the obedience of the people.",
"\n11", "Binding his donkey to the vine, And his", "donkey's colt to the choice vine, He"
)

Answer 1

Please, check this:
library(tidyverse)
split_line_number <- function(x) {
x %>%
str_replace("^([0-9]+)", "\n\\1\b") %>%
str_split("\b")
}
output.by.line %>%
map(split_line_number) %>%
unlist()
# Output:
# [35] "\n49"
# [36] "And Jacob called his sons and"
# [37] "said, \"Gather together, that I may tell"
# [38] "you what shall befall you in the last"

Answer 2

An option using stringr::str_match is to match two components of an optional number followed by everything. Get the captured output from the matched matrix (2:3) and create a new vector of strings by dropping NAs and empty strings.
vals <- c(t(stringr::str_match(output.by.line, "(\n?\\d+)?(.*)")[, 2:3]))
output <- vals[!is.na(vals) & vals != ""]
output[32:39]
#[1] "portion above your brothers, which I"
#[2] "took from the hand of the Amorite with"
#[3] "my sword and my bow.\""
#[4] "49"
#[5] "And Jacob called his sons and"
#[6] "said, \"Gather together, that I may tell"
#[7] "you what shall befall you in the last" "days:"

Answer 3

We'll make use of the stringr package:
library(stringr)
Modify the object:
output.by.line <- unlist(
ifelse(grepl('[[:digit:]][[:alpha:]]', output.by.line), str_split(gsub('([[:digit:]]+)([[:alpha:]])', paste0('\n', '\\1 \\2'), output.by.line), '[[:blank:]]', n = 2), output.by.line)
)
Print the resuts:
dput(output.by.line)
#[32] "portion above your brothers, which I"
#[33] "took from the hand of the Amorite with"
#[34] "my sword and my bow.\""
#[35] "\n49"
#[36] "And Jacob called his sons and"
#[37] "said, \"Gather together, that I may tell"
#[38] "you what shall befall you in the last"