rename sequence numeric data frame column within list

Question

I have a list with other 4 list, each one of list have 7 data frames (with 36 rows and 2 column). I want rename only the second column of data frames with a sequence numeric in ascending order, i try this:

for (i in 1:length(data.Precip)) 
 colnames(data.Precip[[i]])[2] =  paste(colnames(data.Precip[[i]])[2],i , sep = "_")

where "data.precip" is a first list of the 4, so the names of seconds columns of data frame within a list "data.Precip" has this: "PRECIPITACION_1"...."PRECIPITACION_7".

Now, for the other list I want to rename the second column but other order, starting of number 8, i.e. "PRECIPITACION_8"..."PRECIPITACION_14"

For the third list with 7 DF do the same.

My code is:

my.data <- list(data.Precip, data.Rad, data.Velvi, data.Temp)
name.x <- c("Date")
i = i+1
name.y <- paste(colnames(my.data[i])[2], i, sep = "_")
my.data <- lapply(seq(my.data), function(i){
lapply(seq(name.y), function(j){
y <- data.frame(my.data[[i]][[j]])
 return(y)
})
})

But this code doesn't work, any idea for this?

Could you please post a version of your code with some toy dataset that will be runable if we just copy you code? That way we can figure out what you are asking and how to fix it much more easily. — see24
– see24, Commented Jul 18, 2018 at 17:04

Parfait · Accepted Answer · 2018-07-18 20:19:31Z

1

Consider building a corresponding same structure and length object, my.nums, of needed numbers and then run a double Map (wrapper to mapply). This avoids the need to sequentially grow and recall an integer variable with i=i+1. Below demonstrates with random data.

set.seed(7182018)
my.data <- list(data.Precip = replicate(7, data.frame(Date = 1:36, col = runif(36, 0, 50)), simplify = FALSE), 
                data.Rad = replicate(7, data.frame(Date = 1:36, col = runif(36, 0, 50)), simplify = FALSE), 
                data.Velvi = replicate(7, data.frame(Date = 1:36, col = runif(36, 0, 50)), simplify = FALSE), 
                data.Temp = replicate(7, data.frame(Date = 1:36, col = runif(36, 0, 50)), simplify = FALSE))

# LONG FORM
my.nums <- list(names.Precip = lapply(1:7, identity),
                names.Rad = lapply(8:14, identity),
                names.Velvi = lapply(15:21, identity),
                names.Temp = lapply(22:28, identity))    
# SHORT FORM
my.nums <- lapply(seq(1,28, by=7), function(x) lapply(seq(x, x+6), identity))

my.names <- list(names.Precip = lapply(rep("PRECIPITACIO_", 7), identity),
                 names.Rad = lapply(rep("RADIACION_", 7), identity),
                 names.Velvi = lapply(rep("VELOCIDAD.VIENTO_", 7), identity),
                 names.Temp = lapply(rep("TEMPERATURA_", 7), identity))
# FUNCTIONS
name_func <- function(df, m, n) setNames(df, c("Date", paste0(m, n)))
iter_df <- function(df_lst, m_list, n_lst) Map(name_func, df_lst, m_list, n_lst)

my.new.data <- Map(iter_df, my.data, my.names, my.nums)

Output

lapply(my.new.data, function(lst) lapply(lst, names))

$data.Precip
$data.Precip[[1]]
[1] "Date"           "PRECIPITACIO_1"

$data.Precip[[2]]
[1] "Date"           "PRECIPITACIO_2"

$data.Precip[[3]]
[1] "Date"           "PRECIPITACIO_3"

$data.Precip[[4]]
[1] "Date"           "PRECIPITACIO_4"

$data.Precip[[5]]
[1] "Date"           "PRECIPITACIO_5"

$data.Precip[[6]]
[1] "Date"           "PRECIPITACIO_6"

$data.Precip[[7]]
[1] "Date"           "PRECIPITACIO_7"


$data.Rad
$data.Rad[[1]]
[1] "Date"        "RADIACION_8"

$data.Rad[[2]]
[1] "Date"        "RADIACION_9"

$data.Rad[[3]]
[1] "Date"         "RADIACION_10"

$data.Rad[[4]]
[1] "Date"         "RADIACION_11"

$data.Rad[[5]]
[1] "Date"         "RADIACION_12"

$data.Rad[[6]]
[1] "Date"         "RADIACION_13"

$data.Rad[[7]]
[1] "Date"         "RADIACION_14"


$data.Velvi
$data.Velvi[[1]]
[1] "Date"                "VELOCIDAD.VIENTO_15"

$data.Velvi[[2]]
[1] "Date"                "VELOCIDAD.VIENTO_16"

$data.Velvi[[3]]
[1] "Date"                "VELOCIDAD.VIENTO_17"

$data.Velvi[[4]]
[1] "Date"                "VELOCIDAD.VIENTO_18"

$data.Velvi[[5]]
[1] "Date"                "VELOCIDAD.VIENTO_19"

$data.Velvi[[6]]
[1] "Date"                "VELOCIDAD.VIENTO_20"

$data.Velvi[[7]]
[1] "Date"                "VELOCIDAD.VIENTO_21"


$data.Temp
$data.Temp[[1]]
[1] "Date"           "TEMPERATURA_22"

$data.Temp[[2]]
[1] "Date"           "TEMPERATURA_23"

$data.Temp[[3]]
[1] "Date"           "TEMPERATURA_24"

$data.Temp[[4]]
[1] "Date"           "TEMPERATURA_25"

$data.Temp[[5]]
[1] "Date"           "TEMPERATURA_26"

$data.Temp[[6]]
[1] "Date"           "TEMPERATURA_27"

$data.Temp[[7]]
[1] "Date"           "TEMPERATURA_28"

edited Jul 18, 2018 at 20:19

answered Jul 18, 2018 at 17:58

Parfait

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5 Comments

Antonio Bonilla Over a year ago

@Perfait thanks, this code worked perfectly, only one question more, its posible change the name "PRECIPITACION" BY "RADIACION" in the second list, "VELOCIDAD.VIENTO" at third list and "TEMPERATURA" for fourth list?

Parfait Over a year ago

Sure you can. Simply, pass another nested list into the double Map calls. See edit. Do note: Map (mapply) can take an open-ended number of arguments, 2, 3, ... 80!

Antonio Bonilla Over a year ago

sorry, I don´t understand you, in the line iter_df <- function(df_lst, m_list, n_lst) Map(name_func, df_lst, m_list, n_lst) add other list?

Parfait Over a year ago

I added a new my.names list and passed it in the functions as a new argument, m_list.

Antonio Bonilla Over a year ago

Oh, you already made the change the code for the question above? thanks @Parfait.

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