How to subset a list of dataframes in R? - r

Question

I have multiple datasets of physical variables, and I want to do some work on it with R. However, I would like to use a list. Here is my code for 1 of my dataframe :
# Table definition
df.jannuary <- read.table("C:\\...file1.csv", sep=";")
# Subset of the table containing only variables of interest
df.jannuary_sub <- subset(df.jannuary, select=c(2:8, 11:12))
# Column names
colnames(df.jannuary_sub)<-c("year","day","hour","minute","temp_air","temp_eau","humidity_rel","wind_intensity","wind_direction")
# Aggregation of the 4 Year-Day-Hour-Minute columns into a single column and conversion into a POSIXct objet through the temporary column "timestamp"
df.jannuary_sub$timestamp <- as.POSIXct(paste(df.jannuary_sub$year, df.jannuary_sub$day, df.jannuary_sub$hour, df.jannuary_sub$minute), format="%Y %j %H %M", tz="GMT")
# Getting the date with a new format from julian day to normal day into a column called "date"
df.jannuary_sub$date <- format(df.jannuary_sub$timestamp,"%d/%m/%Y %H:%M",tz = "GMT")
# Suppression of the 4 Year-Day-Hour-Minute initial columns and of the temporary column "timestamp", and placement of the date column as column 1
df.jannuary_sub <- subset(df.jannuary_sub, select=c(11, 5:9))
This code works. The thing is I got all the months of the year, for several years.
So I started to use a list, here is the example for the year 2011 :
df.jannuary <- read.table("C:\\...\file1.dat", sep=",")
#...
df.december <- read.table("C:\\...\file12.dat", sep=",")
# Creation of a list containing the month datasets, with a subset of the tables containing only variables of interest
list.dataset_2011<-list(
df.jannuary_sub <- subset(df.jannuary, select=c(2:8, 11:12)),
#...
df.december_sub <- subset(df.december, select=c(2:8, 11:12))
)
# Column names for all variables of the list for (j in 1:12)
{
colnames(list.dataset_2011[[j]])<-c("year","day","hour","minute","temp_air","temp_eau","humidity_rel","wind_intensity","wind_direction")
}
# Conversion of the list into a data.frame called "list.dataset_2011" for (i in 1:9)
{
list.dataset_2011[[i]]<-as.data.frame(list.dataset_2011[[i]])
}
# Aggregation of the 4 Year-Day-Hour-Minute columns into a single column and conversion into a POSIXct objet through the temporary column "timestamp"
list.dataset_2011$timestamp <- as.POSIXct(paste(list.dataset_2011$year, list.dataset_2011$day, list.dataset_2011$hour, list.dataset_2011$minute), format="%Y %j %H %M", tz="GMT")
# Getting the date with a new format from julian day to normal day into a column called "date"
list.dataset_2011$date <- format(list.dataset_2011$timestamp,"%d/%m/%Y %H:%M",tz = "GMT")
# Suppression of the 4 Year-Day-Hour-Minute initial columns and of the temporary column "timestamp", and placement of the date column as column 1
list.dataset_2011 <- subset(list.dataset_2011, select=c(11, 5:9))
I encounter a problem at the end of my code (hoping the rest is working !) with the subset command, which doesn't appear to work for the attribute "list".