Guessing game in R - r

I've tried to create a guessing game in R but it gives me the error with "readinteger". Just started learning R, sorry if it's a too simple question. The idea of the game is to ask a user to choose a random integer from 0 to 10 and if he guesses say something "well done" and if he does not say something like "It's bigger" or "It's smaller" until he guesses the integer.
> num <- round(runif(1) * 10, digits = 0)
> guess <- -1
>
> cat("Guess an integer between 0 and 10.n")
Guess an integer between 0 and 10.n>
> while(guess != num)
+ {
+ guess = readinteger()
+ if (guess == num)
+ {
+ cat("Well done,", num, "is correct.n")
+ }
+ else if (guess < num)
+ {
+ cat("It's bigger!n")
+ }
+ else if(guess > num)
+ {
+ cat("It's smaller!n")
+ }
+ }
Error in readinteger() : could not find function "readinteger"

Maybe you want readline()? I'm guessing you want this. You need to define that function in your script.
readinteger <- function() {
n <- readline(prompt="Enter an integer: ")
return(as.integer(n))
}
num <- round(runif(1) * 10, digits = 0)
guess <- -1
...

Related

Why does a piece of code that works on its own not work in parallel in R?

I wrote a piece of code (appended below) that works fine when I run it in serial, but when I use the foreach and doparallel libraries in R, I get an error code that reads: " task 1 failed - "missing value where TRUE/FALSE needed"
Everything inside the for each loop works on its own, and on a smaller batch, I can run it serially and it works.
ListOfColumns <- colnames(tempdata)
foreach(i = 1:nSubsets,
.export = ls(globalenv())) %dopar% {
DoubleTempData <- get(paste0("Subset", i))
DoubleTempData <- subset(DoubleTempData, select = -c(subset))
RowCounter <- 2
ColumnFigurer <- 2
LastCATEGORYIndicator <- "THERE IS NO CATEGORY, ONLY ZUUL"
while (RowCounter <= nrow(DoubleTempData)) {
print(paste("Checking row ", RowCounter))
RowChecker <- max(1, RowCounter - 5)
while (RowChecker < RowCounter) {
print(paste("Checking row",
RowCounter,
"against row",
RowChecker))
if (DoubleTempData$CATEGORY[RowChecker] == DoubleTempData$CATEGORY[RowCounter])
{
print("The rows match!")
while (ColumnFigurer > 0) {
if (DoubleTempData$CATEGORY[RowCounter] != LastCATEGORYIndicator) {
ColumnFigurer <- 2
}
print(paste ("Checking Iteration", ColumnFigurer))
if (ColumnFigurer * length(ListOfColumns) <= length(colnames(DoubleTempData)))
{
print(paste("Iteration", ColumnFigurer, " exists"))
CellChecker <-
((ColumnFigurer - 1) * length(ListOfColumns) + 1)
if (is.na(DoubleTempData[[RowChecker, CellChecker]])) {
print(paste("Current value is NA. Writing in new value."))
ColumnCounter <- 1
while (ColumnCounter <= length(ListOfColumns)) {
DoubleTempData[[RowChecker, (ColumnFigurer - 1) * length(ListOfColumns) +
ColumnCounter]] <-
DoubleTempData[[RowCounter, ColumnCounter]]
ColumnCounter <- ColumnCounter + 1
}
DoubleTempData <- DoubleTempData[-RowCounter]
LastCATEGORYIndicator <-
DoubleTempData$CATEGORY[RowChecker]
RowCounter <- max(2, RowCounter - 1)
ColumnFigurer <- ColumnFigurer + 1
break
}
else
{
print(paste(
"Current value is not NA, increasing iteration count."
))
ColumnFigurer <- ColumnFigurer + 1
}
}
if (ColumnFigurer * length(ListOfColumns) > length(colnames(DoubleTempData)))
{
print(paste(
"Iteration ",
ColumnFigurer,
"does not exist, adding iteration."
))
ColumnAdder <- 1
while (ColumnAdder <= length(ListOfColumns)) {
NewColumnName <-
paste0(ListOfColumns[ColumnAdder], "_", ColumnFigurer)
DoubleTempData[, NewColumnName] <- NA
ColumnAdder <- ColumnAdder + 1
}
}
}
}
RowChecker <- RowChecker + 1
}
RowCounter <- RowCounter + 1
}
assign(paste0("Subset", i), DoubleTempData)
}
For example, here is a sample of a randomly generated Subset1 that I ran, with about 70 observations and 7 columns (one of which gets dropped by the program as intended):
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/Jlytj.png
It then outputs a dataset with 9 observations, and 60 columns:

Use result of previous loop as input for next loop

I have the code below, which seems to accomplish what I'm trying to do but also throws the error output shown below the code. What I'm trying to do, is run through the loop the first time with x = 1, then for each time the loop runs after that I want x = y, the result of the previous loop. I always fumble with loops so any tips are greatly appreciated.
Code:
for(i in 1:5)
{
if(i=1)
{
x<-1
}
else
{
x<-y
}
y<-x*i
y
}
ERRORS:
for(i in 1:5)
+ {
+ if(i=1)
Error: unexpected '=' in:
"{
if(i="
> {
+ x<-1
+ }
> else
Error: unexpected 'else' in " else"
> {
+ x<-y
+ }
> y<-x*i
> y
[1] 25
> }
Error: unexpected '}' in "}"
Here is your code re-written with slightly clearer syntax
for (i in 1:5) {
if (i == 1) {
x <- 1
} else {
x <- y
}
y <- x * i
}
Or even better syntax.
for (i in 1:5) {
x <- ifelse(i == 1, 1, y)
y <- x * i
}

KnapSack dynamic programming in R with recursive function

I created this simple code in R to solve the Knapsack program with a recursive funtion
n <- c(0,1,2,3,4)
v <- c(10,40,30,50)
w <- c(5,4,6,3)
k <- 10
myfunction <- function(n,k){
if (n==0 | k==0){
output <- 0
} else if (w[i] > k) {
output <- myfunction[i-1,w]
} else {
output <- max(v[i]+ myfunction(i-1, k-w[i]),myfunction(i-1,k))
}
return(myfunction)
}
However, I don't get a value as an output, but the whole function. For example if I put in:
myfunction(4,10)
I don't get an value of 90, but the whole funtion typed out.
these are the values
There were several errors beyond the ones pointed out by #etienne. Here's an annotated debugging session. First we fix the returned object:
> myfunction <- function(n,k){
+ if (n==0 | k==0){
+ output <- 0
+ } else if (w[i] > k) {
+ output <- myfunction[i-1,w]
+ } else {
+ output <- max(v[i]+ myfunction(i-1, k-w[i]),myfunction(i-1,k))
+ }
+ return(output)
+ }
> myfunction(4,10)
Error in if (w[i] > k) { : argument is of length zero
Obviously neither w nor k are of length zero which suggests it must be i. (As also pointed out by etienne). Looking at your code it appears you actually intended i to be the index that decreased until the terminating condition was met. So replace n by i in the few instances where it appeared:
> myfunction <- function(i,k){
+ if (i==0 | k==0){
+ output <- 0
+ } else if (w[i] > k) {
+ output <- myfunction[i-1,w]
+ } else {
+ output <- max(v[i]+ myfunction(i-1, k-w[i]),myfunction(i-1,k))
+ }
+ return(output)
+ }
> myfunction(4,10)
Error in myfunction[i - 1, w] :
object of type 'closure' is not subsettable
So you also made the mistake of using square-brackets where parentheses (aka bracket in the non-US sections of the world) were needed:
> myfunction <- function(i,k){
+ if (i==0 | k==0){
+ output <- 0
+ } else if (w[i] > k) {
+ output <- myfunction(i-1,w)
+ } else {
+ output <- max(v[i]+ myfunction(i-1, k-w[i]),myfunction(i-1,k))
+ }
+ return(output)
+ }
> myfunction(4,10)
[1] 90
Success, well, almost. Most of the warnings are because you used | instead of || in one of the conditionals:
Warning messages:
1: In if (i == 0 | k == 0) { :
the condition has length > 1 and only the first element will be used
2: In if (w[i] > k) { :
the condition has length > 1 and only the first element will be used
3: In if (i == 0 | k == 0) { :
the condition has length > 1 and only the first element will be used
4: In if (i == 0 | k == 0) { :
the condition has length > 1 and only the first element will be used
5: In if (i == 0 | k == 0) { :
the condition has length > 1 and only the first element will be used
6: In if (i == 0 | k == 0) { :
the condition has length > 1 and only the first element will be used
So replace that instance with a logical ||. To deal with the other warning that didn't seem to sabotage your logic, realize that w[i] is length-0 when i == 0, so add a logical clause in the conditional that first tests for that possibility and use the correct "double-AND-sign" ( && ):
myfunction <- function(i,k){
if (i==0 || k==0){
output <- 0
} else if (length( w[i]) && w[i] > k) {
output <- myfunction(i-1,w)
} else {
output <- max(v[i]+ myfunction(i-1, k-w[i]), myfunction(i-1,k))
}
return(output)
}
Now you get:
> myfunction(4,10)
[1] 90

MATLAB to R Conversion: Append values to an existing empty array through for loop

I have the below code with me. This code was written originally in MATLAB. I have two questions here:
1) What would be the corresponding command in R for the below command in MATLAB:
duet(i).p = [];
2) In the below code I am getting all the correct 6 values for duet$n, but I am not getting correct values for duet$p. My question is how to append the values to an empty existing array duet$p[i] in R through the for loop iterations.
This line is not working in the below code:
duet$p[i] <- c(duet$p[i],j)
I might also have declared duet$p[i] <- array() incorrectly.
The values for duet.n and duet.p from MATLAB are:
duet.n
2 0 2 0 1 3
duet.p
[] [3,6] [] [1,3,5,6] [1,6] []
In R, I am getting duet$n values correctly, but I am not able to get the array kind of results for duet$p.
Any help to get the duet$p values would be appreciated.
x <- matrix(c(-1,2,4,1,7,4.2,3,0,1.2,-1.2,5.1,4,2,3.1,1.1,1,1,9,0,1,2,2,8,1,2,2,2,2,2,2),nrow=6,ncol=5,byrow=T)
fro=1;N=6;M=2;V=3;
F <- list(f=c())
duet = list()
for (i = 1 : N){
duet$n[i] = 0
duet$p[i] = array() ## Create an empty array
for (j in 1 : N){
dl = 0
de = 0
dm = 0
for (k = 1 : M){
if (x[i,V + k] < x[j,V + k]){
dl = dl + 1
} else if (x[i,V + k] == x[j,V + k]){
de = de + 1
} else{
dm = dm + 1
}
}
if (dl == 0 & de != M){
duet$n[i] = duet$n[i] + 1
} else if (dm == 0 & de != M){
duet$p[i] = c(duet$p[i],j)
}
}
if (duet$n[i] == 0){
x[i,6] = 1
F$f = c(F$f,i)
}
}
This appears to get the output you want:
x <- matrix(c(-1,2,4,1,7,4.2,3,0,1.2,-1.2,5.1,4,2,3.1,1.1,1,1,9,0,1,2,2,8,1,2,2,2,2,2,2),nrow=6,ncol=5,byrow=T)
fro=1;N=6;M=2;V=3;
F <- list(f=c())
duet = list(n=rep(0,N), p=lapply(1:N, function(x)c()))
for (i in 1 : N){
duet$n[i] = 0
#duet$p[[i]] = c() ## Create an empty array
#if(i==2) browser()
for (j in 1 : N){
k=1:M
dl <- sum(x[i,V + k] < x[j,V + k])
de <- sum(x[i,V + k] == x[j,V + k])
dm <- sum(x[i,V + k] > x[j,V + k])
if (dl == 0 & de != M){
duet$n[i] = duet$n[i] + 1
} else if (dm == 0 & de != M){
duet$p[[i]] = c(duet$p[[i]],j)
}
}
if (duet$n[i] == 0){
#x[i,6] = 1
F$f = c(F$f,i)
}
}
What have I done?
commented out the line x[i,6] =1, because there isn't an x[i,6], and I'm not sure what you meant it to be. You will need to sort this out.
Initialised duet$n as a vector
Initialised duet$p as a list of n empty vectors
removed the k loop as conditional counting in R can be done as the sum of elements where the condition is TRUE.
corrected the syntax of for loops: = became in
I think you're trying to do duet[i]$p instead of what you're doing. Also you need to initialize each cell as a list

Error .. missing value where TRUE/FALSE needed

I have been trying to run this code (below here) and I have gotten that message "Error in if (temp[ii] == 0) { : missing value where TRUE/FALSE needed"...
temp = c(2.15, 3.5, 0, 0, 0, 1.24, 5.42, 6.87)
tm = length(temp)
for (i in 1:tm){
if (temp[i] == 0) {
counter3 = 1
last = temp[i - 1]
for (ii in i + 1:tm){
if (temp[ii] == 0) {
counter3 = counter3 + 1
}
if (temp[ii] != 0) {
nxt = temp[i + counter3]
}
}
}
}
Your problem is that temp[ii] is returning NA because ii goes out of bounds:
ii = i + 1:tm #Your declaration for ii
ii = 1:tm + 1:tm #Evaluates to
So ii will definitely be larger than tm (and therefore length(temp) at some point.
In order to better understand/debug for loops, consider printing just the indices:
for(i in 1:tm)
{
print(i)
for(ii in i + 1:tm)
print(ii)
}
At a guess I'm going to say that this is in R - if so I'm guessing that this line:
if (temp[i] == 0) (or temp[ii] == 0)
is resulting in an NA, and if conditions must have a TRUE or FALSE value.
Using a debugger if you can, I'd interrogate the value of temp[i] before the if block.
Difficult without knowing the language, but i think the issue is that the value in ii can be greater than the length of temp when i is at its upper bound. I'd have expected an index out of range or something similar but, without knowing the language, who knows! Hope you get your problem fixed.

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