Continuing a loop from the next iteration of point of break R - r

Question

There might be a simple solution to this but I'm struggling.
I have a code as follows:
for(i in 1:nrow(df)){
x[i] <- df[i,]$X4
if(length(unique(df[1:i,]$X4)) == length(unique(df$X4))){
break
}
collect <- data.frame(df[1,]$X1, df[1,]$X2, df[i+1,]$X3)
}
The loop breaks after the if condition length(unique(df[1:i,]$X4)) == length(unique(df$X4)) is reached. However, I want to start the same loop again from i+1'th iteration, and keep checking until the same if condition is met again, till the end of my dataframe.
My sample data is as follows:
1 930000 1000000 E2-A
1 1890000 2110000 E2-A
1 2120000 2330000 D
1 2340000 3350000 E2-B
1 3365000 3405000 B
1 5695000 5810000 E2-A
1 6305000 6405000 E2-B
1 6425000 6465000 E1-A
1 6780000 6960000 E2-B
1 7100000 7270000 D
1 7730000 7810000 D
1 8030000 8380000 E2-A
1 8970000 9170000 E1-A
1 9345000 9555000 E1-B
1 9845000 9930000 E1-A
1 10000000 10100000 E1-B
1 10430000 10560000 E3
1 11720000 11780000 B
1 11900000 11960000 C
1 12185000 12270000 E1-A
1 12450000 12680000 A #break point of loop because if(length(unique(df[1:i,]$X4)) == length(unique(df$X4)))
1 13990000 14290000 B
1 15250000 15355000 E2-B
1 15475000 15600000 D
1 15655000 15755000 A
1 15920000 16080000 E2-A
1 16120000 16280000 C
1 16400000 16570000 E1-B
1 17280000 17380000 E1-B
1 17450000 17735000 A
1 17760000 17820000 E1-B
1 17825000 17935000 A
1 18925000 19150000 E1-A
1 19220000 19410000 C
1 19680000 19980000 C
1 20230000 20820000 E3 #the if condition is met again after the break, but using break exits the loop
1 20845000 20970000 E2-A
1 21580000 21695000 D
1 21700000 21920000 E2-A
1 22430000 22750000 B
1 22740000 22980000 A
1 23300000 23515000 C
1 23870000 23965000 A
1 24525000 24720000 E2-B
1 25010000 25160000 D
1 25170000 25430000 B
1 25930000 26130000 A
1 26220000 26330000 E2-B
1 26435000 26485000 C
My expected output is:
1 930000 12680000
1 13990000 20820000
But what I get so far is:
1 930000 12680000
How do I do so?

Answer 1

# I saved the data you provided into a file and read them back into R session
df <- read.table("df.txt",quote="#")
# It looks like you are using X1, X2, and so on in your code example
# so I renamed the column names
names(df) <- c("X1","X2","X3","X4")
# check the structure of the data frame
str(df)
# 'data.frame': 49 obs. of 4 variables:
# $ X1: int 1 1 1 1 1 1 1 1 1 1 ...
# $ X2: int 930000 1890000 2120000 2340000 3365000 5695000 6305000 6425000 6780000 7100000 ...
# $ X3: int 1000000 2110000 2330000 3350000 3405000 5810000 6405000 6465000 6960000 7270000 ...
# $ X4: Factor w/ 9 levels "A","B","C","D",..: 7 7 4 8 2 7 8 5 8 4 ...
result <- list()
i.new = 1
j = 0
# number of unique values in the 4th column
n.unique <- length(unique(df$X4))
for ( i in seq(nrow(df) )) {
if(length(unique(df[i.new : i,"X4" ])) == n.unique ){
j = j+1
result[[j]] <- c( df[i.new, 2], df[i, 3])
i.new = i + 1
}
}
result
# [[1]]
# [1] 930000 12680000
#
# [[2]]
# [1] 13990000 20820000
# If Dataframe is needed:
do.call(rbind.data.frame, result)
#c.930000L..13990000L. c.12680000L..20820000L.
#1 930000 12680000
#2 13990000 20820000
#If matrix is OK
matrix(unlist(result, use.names=F), ncol = 2, byrow = TRUE)
# [,1] [,2]
#[1,] 930000 12680000
#[2,] 13990000 20820000

Answer 2

ulist<- unique(df$X4)
uniq <- length(unique(df$X4))
brk <- 0
rn <- length(df$X1)
coor <- NULL
while (brk < rn) {
found <- rep(0,uniq)
coor.s <- 0
coor.e <- 0
coor.s <- df$X2[brk+1]
for (i in (brk+1):rn) {
for (j in 1:uniq) {
if(df$X4[i] == ulist[j]) {found[j]<-1}
}
if (sum(found)==uniq) {coor.e <- df$X3[i];brk=i;break}
}
if(sum(found)<uniq) {
break
} else {
collect.df <- as.data.frame(rbind(coor,c(coor.s,coor.e)))
}
}