I am a new user of R and trying to use mRMRe R package (mRMR is one of the good and well known feature selection approaches) to obtain feature subset from a feature set. Please excuse if my question is simple as I really want to know how I can fix an error. Below is the detail.
Suppose, I have a csv file (gene.csv) having feature set of 6 attributes ([G1.1.1.1], [G1.1.1.2], [G1.1.1.3], [G1.1.1.4], [G1.1.1.5], [G1.1.1.6]) and a target class variable [Output] ('1' indicates positive class and '-1' stands for negative class). Here's a sample gene.csv file:
[G1.1.1.1] [G1.1.1.2] [G1.1.1.3] [G1.1.1.4] [G1.1.1.5] [G1.1.1.6] [Output]
11.688312 0.974026 4.87013 7.142857 3.571429 10.064935 -1
12.538226 1.223242 3.669725 6.116208 3.363914 9.174312 1
10.791367 0.719424 6.115108 6.47482 3.597122 10.791367 -1
13.533835 0.37594 6.766917 7.142857 2.631579 10.902256 1
9.737828 2.247191 5.992509 5.992509 2.996255 8.614232 -1
11.864407 0.564972 7.344633 4.519774 3.389831 7.909605 -1
11.931818 0 7.386364 5.113636 3.409091 6.818182 1
16.666667 0.333333 7.333333 4.333333 2 8.333333 -1
I am trying to get best feature subset of 2 attributes (out of above 6 attributes) and wrote following R code.
library(mRMRe)
file_n<-paste0("E:\\gene", ".csv")
df <- read.csv(file_n, header = TRUE)
f_data <- mRMR.data(data = data.frame(df))
featureData(f_data)
mRMR.ensemble(data = f_data, target_indices = 7,
feature_count = 2, solution_count = 1)
When I run this code, I am getting following error for the statement f_data <- mRMR.data(data = data.frame(df)):
Error in .local(.Object, ...) :
data columns must be either of numeric, ordered factor or Surv type
However, data in each column of the csv file are real number.So, how can I change the R code to fix this problem? Also, I am not sure what should be the value of target_indices in the statement mRMR.ensemble(data = f_data, target_indices = 7,feature_count = 2, solution_count = 1) as my target class variable name is "[Output]" in the gene.csv file.
I will appreciate much if anyone can help me to obtain the best feature subset based on the gene.csv file using mRMRe R package.
I solved the problem by modifying my code as follows.
library(mRMRe)
file_n<-paste0("E:\\gene", ".csv")
df <- read.csv(file_n, header = TRUE)
df[[7]] <- as.numeric(df[[7]])
f_data <- mRMR.data(data = data.frame(df))
results <- mRMR.classic("mRMRe.Filter", data = f_data, target_indices = 7,
feature_count = 2)
solutions(results)
It worked fine. The output of the code gives the indices of the selected 2 features.
I think it has to do with your Output column which is probably of class integer. You can check that using class(df[[7]]).
To convert it to numeric as required by the warning, just type:
df[[7]] <- as.numeric(df[[7]])
That worked for me.
As for the other question, after reading the documentation, setting target_indices = 7 seems the right choice.
Related
I want to use the apriori algorithm to apply association rules between words on the tweet database I have with RStudio. However, the code below gives an error on a million rows of data, while working on a small number of data. I needed your help as I couldn't understand what caused the error.
TweetTrans <- read.transactions("../input/tweets/output.csv",
rm.duplicates=FALSE,
format = "basket",
sep = ",",
encoding = "UTF-8")
The Error is:
Error in validObject(.Object): invalid class “ngCMatrix” object: row indices are not sorted within columns
Traceback:
1. read.transactions("../input/tweets/output.csv", rm.duplicates = FALSE,
. format = "basket", sep = ",", encoding = "UTF-8")
2. as(data, "transactions")
3. asMethod(object)
4. new("transactions", as(from, "itemMatrix"), itemsetInfo = data.frame(transactionID = names(from),
. stringsAsFactors = FALSE))
5. initialize(value, ...)
6. initialize(value, ...)
7. callNextMethod()
8. .nextMethod(.Object = .Object, ... = ...)
9. callNextMethod()
10. .nextMethod(.Object = .Object, ... = ...)
11. as(from, "itemMatrix")
12. asMethod(object)
13. new("ngCMatrix", p = c(0L, p), i = as.integer(i) - 1L, Dim = c(length(levels(i)),
. length(p)))
14. initialize(value, ...)
15. initialize(value, ...)
16. callNextMethod()
17. .nextMethod(.Object = .Object, ... = ...)
18. validObject(.Object)
19. stop(msg, ": ", errors, domain = NA)
Here are some ideas for how to find a rogue line in the data file. The input to read.transactions should be a text file the looks something like
A, B, C
B, C
C, D, E
D, A, B, F
where A, B ,C, etc are the names of the items (probably longer than one character each!)
So you could read in the file using readLines...
data <- readLines("../input/tweets/output.csv")
Each element of data (one per line of the file) should be a string of the form "A, B, C" etc, as above.
You could then use functions (e.g. from the stringr package) to check if any lines contain unusual characters, or have an odd format. Without seeing your file, it is hard to say how to do this, but you might, for example, look for quotes in odd places (str_detect(data, '\\"')) or characters that are not letters, digits , spaces or commas (str_detect(data, "[^\\w\\d\\s,]")).
Another thing you could try is to write a for loop to take each element of data (or perhaps larger chunks if that is too slow), save it as a file, try reading it with read.transactions, and see where it crashes.
for(i in seq_along(data)){
writeLines(data[i], "dummyfile.csv")
trans <- read.transactions("dummyfile.csv",
rm.duplicates=FALSE,
format = "basket",
sep = ",",
encoding = "UTF-8")
}
The value of i when it crashes will give you the problem row number. It might take a long time to run, though!
I ran into a very similar problem: the same error got triggered when trying to cast a list to a transaction object.
I also couldn't easily figure out what lines in the data caused the issue, as it seems to be triggered by a combination of transactions and not necessarily by any individual one, but I managed to track down the source of the problem in this assignment (source):
p <- new("ngCMatrix", p = c(0L, p),
i = as.integer(i) - 1L,
Dim = c(length(levels(i)), length(p)))
My R got pretty rusty over time and I couldn't find an immediate way to patch the code, but I came up with an alternative solution for constructing the ngCMatrix object:
Assume you have the data in a data.frame following some sort of (user, item) format - in your case it would most likely be (tweet_id, term/word)
Create a unique incremental ID for every user and item and add it to your data.frame
Use those ID to create the sparse matrix and - optionally - enrich it with the labels for item and user to make it more interpretable
Finally, cast the sparse matrix to a transaction object
Example (I implemented mine with data.table, but a traditional dataframe implementation would be very similar):
library(Matrix)
library(data.table)
library(arules)
DT <- data.table(user = c('A','A','B','B','A','C','D'),
item = c('AAB','AAA','AAB','BBB','ABA','BBB','AAB'))
# Create user_ids
unique_users <- unique(DT$user)
users <- data.table(user=unique_users,
user_id=c(1:length(unique_users)))
# Repeat for items
unique_items <- unique(DT$item)
items <- data.table(item=unique_items,
item_id=c(1:length(unique_items)))
# Add indexes to original data table (setting keys helps with performance)
DT <- merge.data.table(x=DT, y=users, by='user')
DT <- merge.data.table(x=DT, y=items, by='item')
# Create the sparse matrix
mat <- sparseMatrix(
i = DT$item_id,
j = DT$user_id,
dims = c(nrow(items), nrow(users)),
dimnames = list(items$item, users$user)
)
# transform to arules 'transactions'
txn <- as(op, "transactions")
Please note that this doesn't help understanding what caused the issue, but rather provides a workaround to solve it. In my data.table implementation the code is pretty performant, taking only a few seconds to process over 30M transactions on a laptop-sized machine (2 CPUs, 16gb RAM).
I have 24 variables called empl_1 -empl_24 (e.g. empl_2; empl_3..)
I would like to write a loop in R that takes this values 1-24 and puts them in the respective places so the corresponding variables are either called or created with i = 1-24. The sample below shows what I would like to have within the loop (e.g. ye1- ye24; ipw_atet_1 - ipw_atet_14 and so on.
ye1_ipw <- empl$empl_1[insample==1]
ipw_atet_1 <- treatweight(y=ye1_ipw, d=treat_ipw, x=x1_ipw, ATET =TRUE, trim=0.05, boot = 2)
ipw_atet_1
ipw_atet_1$se
ye2_ipw <- empl$empl_2[insample==1]
ipw_atet_2 <- treatweight(y=ye2_ipw, d=treat_ipw, x=x1_ipw, ATET =TRUE, trim=0.05, boot = 2)
ipw_atet_2
ipw_atet_2$se
ye3_ipw <- empl$empl_3[insample==1]
ipw_atet_3 <- treatweight(y=ye3_ipw, d=treat_ipw, x=x1_ipw, ATET =TRUE, trim=0.05, boot = 2)
ipw_atet_3
ipw_atet_3$se
coming from a Stata environment I tried
for (i in seq_anlong(empl_list)){
ye[i]_ipw <- empl$empl_[i][insample==1]
ipw_atet_[i]<-treatweight(y=ye[i]_ipw, d=treat_ipw, x=x1_ipw, ATET=TRUE, trim=0.05, boot =2
}
However this does not work at all. Do you have any idea how to approach this problem by writing a nice loop? Thank you so much for your help =)
You can try with lapply :
result <- lapply(empl[paste0('empl_', 1:24)], function(x)
treatweight(y = x[insample==1], d = treat_ipw,
x = x1_ipw, ATET = TRUE, trim = 0.05, boot = 2))
result would be a list output storing the data of all the 24 variables in same object which is easier to manage and process instead of having different vectors.
I am relatively beginner in R and trying to figure out how to use cpquery function for bnlearn package for all edges of DAG.
First of all, I created a bn object, a network of bn and a table with all strengths.
library(bnlearn)
data(learning.test)
baynet = hc(learning.test)
fit = bn.fit(baynet, learning.test)
sttbl = arc.strength(x = baynet, data = learning.test)
Then I tried to create a new variable in sttbl dataset, which was the result of cpquery function.
sttbl = sttbl %>% mutate(prob = NA) %>% arrange(strength)
sttbl[1,4] = cpquery(fit, `A` == 1, `D` == 1)
It looks pretty good (especially on bigger data), but when I am trying to automate this process somehow, I am struggling with errors, such as:
Error in sampling(fitted = fitted, event = event, evidence = evidence, :
logical vector for evidence is of length 1 instead of 10000.
In perfect situation, I need to create a function that fills the prob generated variable of sttbl dataset regardless it's size. I tried to do it with for loop to, but stumbled over the error above again and again. Unfortunately, I am deleting failed attempts, but they were smt like this:
for (i in 1:nrow(sttbl)) {
j = sttbl[i,1]
k = sttbl[i,2]
sttbl[i,4]=cpquery(fit, fit$j %in% sttbl[i,1]==1, fit$k %in% sttbl[i,2]==1)
}
or this:
for (i in 1:nrow(sttbl)) {
sttbl[i,4]=cpquery(fit, sttbl[i,1] == 1, sttbl[i,2] == 1)
}
Now I think I misunderstood something in R or bnlearn package.
Could you please tell me how to realize this task with filling the column by multiple cpqueries? That would help me a lot with my research!
cpquery is quite difficult to work with programmatically. If you look at the examples in the help page you can see the author uses eval(parse(...)) to build the queries. I have added two approaches below, one using the methods from the help page and one using cpdist to draw samples and reweighting to get the probabilities.
Your example
library(bnlearn); library(dplyr)
data(learning.test)
baynet = hc(learning.test)
fit = bn.fit(baynet, learning.test)
sttbl = arc.strength(x = baynet, data = learning.test)
sttbl = sttbl %>% mutate(prob = NA) %>% arrange(strength)
This uses cpquery and the much maligned eval(parse(...)) -- this is the
approach the the bnlearn author takes to do this programmatically in the ?cpquery examples. Anyway,
# You want the evidence and event to be the same; in your question it is `1`
# but for example using learning.test data we use 'a'
state = "\'a\'" # note if the states are character then these need to be quoted
event = paste(sttbl$from, "==", state)
evidence = paste(sttbl$to, "==", state)
# loop through using code similar to that found in `cpquery`
set.seed(1) # to make sampling reproducible
for(i in 1:nrow(sttbl)) {
qtxt = paste("cpquery(fit, ", event[i], ", ", evidence[i], ",n=1e6", ")")
sttbl$prob[i] = eval(parse(text=qtxt))
}
I find it preferable to work with cpdist which is used to generate random samples conditional on some evidence. You can then use these samples to build up queries. If you use likelihood weighting (method="lw") it is slightly easier to do this programatically (and without evil(parse(...))).
The evidence is added in a named list i.e. list(A='a').
# The following just gives a quick way to assign the same
# evidence state to all the evidence nodes.
evidence = setNames(replicate(nrow(sttbl), "a", simplify = FALSE), sttbl$to)
# Now loop though the queries
# As we are using likelihood weighting we need to reweight to get the probabilities
# (cpquery does this under the hood)
# Also note with this method that you could simulate from more than
# one variable (event) at a time if the evidence was the same.
for(i in 1:nrow(sttbl)) {
temp = cpdist(fit, sttbl$from[i], evidence[i], method="lw")
w = attr(temp, "weights")
sttbl$prob2[i] = sum(w[temp=='a'])/ sum(w)
}
sttbl
# from to strength prob prob2
# 1 A D -1938.9499 0.6186238 0.6233387
# 2 A B -1153.8796 0.6050552 0.6133448
# 3 C D -823.7605 0.7027782 0.7067417
# 4 B E -720.8266 0.7332107 0.7328657
# 5 F E -549.2300 0.5850828 0.5895373
I'm trying to write an xlsx file from a list of dataframes that I created but I'm getting an error due to missing data (I couldn't download it). I just want to write the xlsx file besides having this lacking data. Any help is appreciated.
For replication of the problem:
library(quantmod)
name_of_symbols <- c("AKER","YECO","SNOA")
research_dates <- c("2018-11-19","2018-11-19","2018-11-14")
my_symbols_df <- lapply(name_of_symbols, function(x) tryCatch(getSymbols(x, auto.assign = FALSE),error = function(e) { }))
my_stocks_OHLCV <- list()
for (i in 1:3) {
trade_date <- paste(as.Date(research_dates[i]))
OHLCV_data <- my_symbols_df[[i]][trade_date]
my_stocks_OHLCV[[i]] <- data.frame(OHLCV_data)
}
And you can see the missing data down here in my_stocks_OHLCV[[2]] and the write.xlsx error I'm getting:
print(my_stocks_OHLCV)
[[1]]
AKER.Open AKER.High AKER.Low AKER.Close AKER.Volume AKER.Adjusted
2018-11-19 2.67 3.2 1.56 1.75 15385800 1.75
[[2]]
data frame with 0 columns and 0 rows
[[3]]
SNOA.Open SNOA.High SNOA.Low SNOA.Close SNOA.Volume SNOA.Adjusted
2018-11-14 1.1 1.14 1.01 1.1 107900 1.1
write.xlsx(my_stocks_OHLCV, "C:/Users/MICRO/Downloads/Datasets_stocks/dux_OHLCV.xlsx")
Error in (function (..., row.names = NULL, check.rows = FALSE,
check.names = TRUE,:arguments imply differing number of rows: 1, 0
How do I run write.xlsx even though I have this missing data?
The main question you need to ask is, what do you want instead?
As you are working with stock data, the best idea, is that if you don't have data for a stock, then remove it. Something like this should work,
my_stocks_OHLCV[lapply(my_stocks_OHLCV,nrow)>0]
If you want a row full of NA or 0
Then use the lapply function and for each element of the list, of length 0, replace with either NA's, vector of 0's (c(0,0,0,0,0,0)) etc...
Something like this,
condition <- !lapply(my_stocks_OHLCV,nrow)>0
my_stocks_OHLCV[condition] <- data.frame(rep(NA,6))
Here we define the condition variable, to be the elements in the list where you don't have any data. We can then replace those by NA or swap the NA for 0. However, I can't think of a reason to do this.
A variation on your question, and one you could handle inside your for loop, is to check if you have data, and if you don't, replace the values there, with NAs, and you could given it the correct headers, as you know which stock it relates to.
Hope this helps.
I am trying to make a function of my own to subset a data.cube in R, and format the result automatically for some predefined plots I aim to build.
This is my function.
require(data.table)
require(data.cube)
secciona <- function(cubo = NULL,
fecha_valor = list(),
loc_valor = list(),
prod_valor = list(),
drop = FALSE){
cubo[fecha_valor, loc_valor, prod_valor, drop = drop]
## The line above will really be an asignment of type y <- format(cubo[...drop])
## Rest of code which will end up plotting the subset of the function
}
The thing is I keep on getting the error: Error in eval(expr, envir, enclos) : object 'fecha_valor' not found
What is most strange for me, is that on the console everything works fine, but not when defined inside the subsetting function of mine.
In console:
> dc[list(as.Date("2013/01/01"))]
> dc[list(as.Date("2013/01/01")),]
> dc[list(as.Date("2013/01/01")),,]
> dc[list(as.Date("2013/01/01")),list(),list()]
all give as result:
<data.cube>
fact:
5627 rows x 2 dimensions x 1 measures (0.32 MB)
dimensions:
localizacion : 4 entities x 3 levels (0.01 MB)
producto : 153994 entities x 3 levels (21.29 MB)
total size: 21.61 MB
But whenever I try
secciona(dc)
secciona(dc, fecha_valor = list(as.Date("2013/01/01")))
secciona(dc, fecha_valor = list())
I always get the error above mentioned.
Any ideas why this is happening? should I proceed in else way for my approach of editing the subset for plotting?
This is the standard issue that R users will face when dealing with non-standard evaluation. This is a consequence of Computing on the language R language feature.
[.data.cube function expects to be used in interactive way, that extends the flexibility of the arguments passed to it, but gives some restrictions. In that aspect it is similar to [.data.table when passing expressions from wrapper function to [ subset operator. I've added dummy example to make it reproducible.
I see you are already using data.cube-oop branch, so just to clarify for other readers. data.cube-oop branch is 92 commits ahead of master branch, to install use the following.
install.packages("data.cube", repos = paste0("https://", c(
"jangorecki.gitlab.io/data.cube",
"Rdatatable.github.io/data.table",
"cran.rstudio.com"
)))
library(data.cube)
set.seed(1)
ar = array(rnorm(8,10,5), rep(2,3),
dimnames = list(color = c("green","red"),
year = c("2014","2015"),
country = c("IN","UK"))) # sorted
dc = as.data.cube(ar)
f = function(color=list(), year=list(), country=list(), drop=FALSE){
expr = substitute(
dc[color=.color, year=.year, country=.country, drop=.drop],
list(.color=color, .year=year, .country=country, .drop=drop)
)
eval(expr)
}
f(year=list(c("2014","2015")), country="UK")
#<data.cube>
#fact:
# 4 rows x 3 dimensions x 1 measures (0.00 MB)
#dimensions:
# color : 2 entities x 1 levels (0.00 MB)
# year : 2 entities x 1 levels (0.00 MB)
# country : 1 entities x 1 levels (0.00 MB)
#total size: 0.01 MB
You can track the expression just by putting print(expr) before/instead eval(expr).
Read more about non-standard evaluation:
- R Language Definition: Computing on the language
- Advanced R: Non-standard evaluation
- manual of substitute function
And some related SO questions:
- Passing on non-standard evaluation arguments to the subset function
- In R, why is [ better than subset?