I am having issues with a loop involving grepl. I am trying to print the index that contains the string "Taxable Revenue by Area", but I keep getting the error Argument is of length zero. I have tried it different ways but keep getting an error. When I check the length of the grepl statement, it is 1, not zero. I'm really stuck! nevlists is a list of dataframes. Each data frame is named by number, 1-48 and the length of nevlists therefore is 48. When I run the grepl statement on its own with the page I want: grepl("Taxable Revenue by Area", nevlists$'48'[3,] this evaluates as TRUE which is what I'm looking for. I just can't adapt this to the loop for whatever reason.
library(readr)
library(stringr)
library(magrittr)
library(dplyr)
library(tidyr)
library(pdftools)
nvsr65_05 <- pdf_text("https://gaming.nv.gov/modules/showdocument.aspx?documentid=13542")
getstats<- function(nvsr65_05){
listofdfs <- list() #Create a list in which you intend to save your df's.
for (i in 1:length(nvsr65_05)) {
table_data2 <- nvsr65_05[[i]] %>%
str_split(pattern = "\n")
table_data2 <- data.frame(matrix(unlist(table_data2)))
listofdfs[[i]] <- table_data2
}
return(listofdfs)
}
nevlists <- getstats(nvsr65_05)
names(nevlists) <-c(1:48)
for (i in 1:length(nevlists)) {
if(grepl("Taxable Revenue by Area", nevlists$'i'[3,]) == TRUE){
print(i)}}
#Try2
for (i in 1:length(nevlists)) {
if(as.numeric(grepl("Taxable Revenue by Area", nevlists$'i'[3,])) > 0){
print(i)}}
I'm not 100% sure, but I think this is due to the way you're indexing- try:
for (i in names(nevlists)) {
# Get the index as a character instead of numeric
# in case your names are something other than pure numbers as
# in this example
ix = paste(i)
if (grepl("Taxable Revenue by Area", nevlists[[ix]][3, ]) == TRUE) {
print(ix)
}
}
This does only print "48" for me- is that what you expect?
If you don't actually care about the name of the list item, you can ignore naming the list items at all and just do:
for (i in 1:length(nevlists)) {
if (grepl("Taxable Revenue by Area", nevlists[[i]][3, ]) == TRUE) {
print(i)
}
}
to output a numeric index value, which may be more useful depending on what you're after.
Related
I have the following code:
df<- iris
library(svDialogs)
columnFunction <- function (x) {
column.D <- dlgList(names(x), multiple = T, title = "Spalten auswaehlen")$res
if (!length((column.D))) {
cat("No column selected\n")
} else {
cat("The following columns are choosen:\n")
print(column.D)
for (z in column.D) {
x[[z]] <- NULL #with this part I wanted to delete the above selected columns
}
}
}
columnFunction(df)
So how is it possible to address data.frame columns "dynamically" so: x[[z]] <- NULL should translate to:
df$Species <- NULL
df[["Species"]] <- NULL
df[,"Species"] <- NULL
and that for every selected column in every data.frame chosen for the function.
Well does anyone know how to archive something like that? I tried several things like with the paste command or sprintf, deparse but i didnt get it working. I also tied to address the data.frame as a global variable by using <<- but didn`t help, too. (Well its the first time i even heard about that). It looks like i miss the right method transferring x and z to the variable assignment.
If you want to create a function columnFunction that removes columns from a passed data frame df, all you need to do is pass the data frame to the function, return the modified version of df, and replace df with the result:
library(svDialogs)
columnFunction <- function (x) {
column.D <- dlgList(names(x), multiple = T, title = "Spalten auswaehlen")$res
if (!length((column.D))) {
cat("No column selected\n")
} else {
cat("The following columns are choosen:\n")
print(column.D)
x <- x[,!names(x) %in% column.D]
}
return(x)
}
df <- columnFunction(df)
I have a list of elements in a random order. I want to read each element of this data one at a time and insert into other list in a sorted order. I wonder how to do this in R. I tried the below code.
lst=list()
x=c(2,3,1,4,5)
for(i in 1:length(x)) ## for reading the elements from x
{
if(lst==NULL)
{
lst=x[i]
}
else
{
lst=x[i]
print(lst)
for(k in 2: length(lst)) ## For sorting the elements in a list
{
value = lst[k]
j=k-1
while(j>=1 && lst[j]>value)
{
lst[j+1] = lst[j]
j= j-1
}
lst[j+1] = value
}
}
print(lst)
}
But i get the the Error :
error in if (lst == NULL) { : argument is of length zero.
For big datasets with lots of columns, you can use do.call
df1 <- df[do.call(order, df),]
Checking the order by specifying the column names,
df2 <- df[with(df, order(V1, V2, V3, V4)),]
identical(df1,df2)
#[1] TRUE
If you need to order in the reverse direction
df[do.call(order, c(df,decreasing=TRUE)),]
data
set.seed(24)
df <- as.data.frame(matrix(sample(letters,10*4,replace=TRUE),ncol=4))
First off, as commenters as pointed, you could use sort or order. But I believe you are trying to solve an assignment.
Your problem is a typo. Try executing in a console:
lst <- list()
lst == NULL
The last line evaluates to a null-length vector (logical(0)) for which R has no interpretation. Instead you are interested in
is.null(lst)
which will return TRUE or FALSE.
UPDATE
Thanks to the help and suggestions of #CarlWitthoft my code was simplified to this:
model <- unlist(sapply(1:length(model.list),
function(i) ifelse(length(model.list[[i]][model.lookup[[i]]] == "") == 0,
NA, model.list[[i]][model.lookup[[i]]])))
ORIGINAL POST
Recently I read an article on how vectorizing operations in R instead of using for loops are a good practice, I have a piece of code where I used a big for loop and I'm trying to make it a vector operation but I cannot find the answer, could someone help me? Is it possible or do I need to change my approach? My code works fine with the for loop but I want to try the other way.
model <- c(0)
price <- c(0)
size <- c(0)
reviews <- c(0)
for(i in 1:length(model.list)) {
if(length(model.list[[i]][model.lookup[[i]]] == "") == 0) {
model[i] <- NA
} else {
model[i] <- model.list[[i]][model.lookup[[i]]]
}
if(length(model.list[[i]][price.lookup[[i]]] == "") == 0) {
price[i] <- NA
} else {
price[i] <- model.list[[i]][price.lookup[[i]]]
}
if(length(model.list[[i]][reviews.lookup[[i]]] == "") == 0) {
reviews[i] <- NA
} else {
reviews[i] <- model.list[[i]][reviews.lookup[[i]]]
}
size[i] <- product.link[[i]][size.lookup[[i]]]
}
Basically the model.list variable is a list from which I want to extract a particular vector, the location from that vector is given by the variables model.lookup, price.lookup and reviews.lookup which contain logical vectors with just one TRUE value which is used to return the desired vector from model.list. Then every cycle of the for loop the extracted vectors are stored on variables model, price, size and reviews.
Could this be changed to a vector operation?
In general, try to avoid if when not needed. I think your desired output can be built as follows.
model <- unlist(sapply(1:length(model.list), function(i) model.list[[i]][model.lookup[[i]]]))
model[model=='']<-NA
And the same for your other variables. This assumes that all model.lookup[[i]] are of length one. If they aren't, you won't be able to write the output to a single element of model in the first place.
I would also note that you are grossly overcoding, e.g. x<-0 is better than x<-c(0), and don't bother with length evaluation on a single item.
I'm new to R. I have a problem to solve, and a working function below that solves it nicely (in decent time). But, from what I'm reading on R tutorials, and here on SO, I feel like I'm doing way too much work to solve it. Is there some fancy R way to collapse this all into a few lines?
The problem to solve: Given a CSV file of data of character data, and a "flag" argument, extract the value at position [row, 1]. "row" is calculated to be the minimum value from column "InterestingColumn" for "flag a", the maximum value from column "Interesting Column" for "flag b", or the n-th value defined by a numeric "flag". The output should be grouped by the unique values of "InterestingColumn". The returned result should be a data frame. The column schema is known, but the length of the file is not.
My instinct is that I should be able to get rid of the for loop altogether, and also that my reconstruction of the matrix with rbind each time is inefficient (like this?) Any tutelage would be appreciated, thanks!
myfunc <- function(flag = "a") {
csv <- read.csv("data.csv", colClasses = "character")
col <- unique(csv$InterestingColumn)
output <- NULL
for (i in 1:length(col)) {
sub <- subset(csv, InterestingColumn == col[i])
vals <- as.numeric(sub[, 12])
if (flag == "a") {
output <- rbind(output, matrix(c(sub[which.min(vals),1], col[i]), ncol = 2))
}
else if (flag == "b") {
output <- rbind(output, matrix(c(sub[which.max(vals),1], col[i]), ncol = 2))
}
else if (is.numeric(flag)) {
output <- rbind(output, matrix(c(sub[flag,1], col[i]), ncol = 2))
}
colnames(output) <- c("data", "col")
as.data.frame(output)
}
}
Say that column 12 is named Col12. Then aggregate may be in order. Everything after the read.csv call in the function should be handled by the following expression (but you may want to set the names of the resulting data frame):
aggregate(Col12 ~ InterestingColumn, data=csv, FUN=function(x) {
if (flag == "a") {
min(x);
} else if (flag == "b") {
max(x);
} else if (is.numeric(flag)) {
x[flag];
}
})
I have a "hit list" of genes in a matrix. Each row is a hit, and the format is "chromosome(character) start(a number) stop(a number)." I would like to see which of these hits overlap with genes in the fly genome, which is a matrix with the format "chromosome start stop gene"
I have the following function that works (prints a list of genes from column 4 of dmelGenome):
geneListBuild <- function(dmelGenome='', hitList='', binSize='', saveGeneList='')
{
genomeColumns <- c('chr', 'start', 'stop', 'gene')
genome <- read.table(dmelGenome, header=FALSE, col.names = genomeColumns)
chr <- genome[,1]
startAdjust <- genome[,2] - binSize
stopAdjust <- genome[,3] + binSize
gene <- genome[,4]
genome <- data.frame(chr, startAdjust, stopAdjust, gene)
hits <- read.table(hitList, header=TRUE)
chrHits <- hits[hits$chr == "chr3R",]
chrGenome <- genome[genome$chr == "chr3R",]
genes <- c()
for(i in 1:length(chrHits[,1]))
{
for(j in 1:length(chrGenome[,1]))
{
if( chrHits[i,2] >= chrGenome[j,2] && chrHits[i,3] <= chrGenome[j,3] )
{
print(chrGenome[j,4])
}
}
}
genes <- unique(genes[is.finite(genes)])
print(genes)
fileConn<-file(saveGeneList)
write(genes, fileConn)
close(fileConn)
}
however, when I substitute print() with:
genes[j] <- chrGenome[j,4]
R returns a vector that has some values that are present in chrGenome[,1]. I don't know how it chooses these values, because they aren't in rows that seem to fulfill the if statement. I think it's an indexing issue?
Also I'm sure that there is a more efficient way of doing this. I'm new to R, so my code isn't very efficient.
This is similar to the "writing the results from a nested loop into another vector in R," but I couldn't fix it with the information in that thread.
Thanks.
I believe the inner loop could be replaced with:
gene.in <- ifelse( chrHits[i,2] >= chrGenome[,2] & chrHits[i,3] <= chrGenome[,3],
TRUE, FALSE)
Then you can use that logical vector to select what you want. Doing
which(gene.in)
might also be of use to you.