R: gsub - Replace months (currently numbers to real names of months)

Question

I've a data frame with the column: "Mes"... it is a numeric vector. It has 1 for January, 2 for February, and so on. But i need the names of the months.

This is my code:

What can i do to get what i need?

For example "Diciembre" is transform to: "EneroFebrero".

df$Mes <- gsub(1, "Enero", df$Mes)
df$Mes <- gsub(2, "Febrero", df$Mes)
df$Mes <- gsub(3, "Marzo", df$Mes)
df$Mes <- gsub(4, "Abril", df$Mes)
df$Mes <- gsub(5, "Mayo", df$Mes)
df$Mes <- gsub(6, "Junio", df$Mes)
df$Mes <- gsub(7, "Julio", df$Mes)
df$Mes <- gsub(8, "Agosto", df$Mes)
df$Mes <- gsub(9, "Setiembre", df$Mes)
df$Mes <- gsub(10, "Octubre", df$Mes)
df$Mes <- gsub(11, "Noviembre", df$Mes)
df$Mes <- gsub(12, "Diciembre", df$Mes)

Results:

When i apply: "unique(df$Mes)": get this:

 [1] "Enero"        "Febrero"      "Marzo"        "Abril"        "Mayo"         "Junio"       
 [7] "Julio"        "Agosto"       "Setiembre"    "Enero0"       "EneroEnero"   "EneroFebrero"

Instead of `gsub`, why not use `function` or basic matching? — A5C1D2H2I1M1N2O1R2T1, Mar 03 '15 at 04:24
@Pascal - is `month.name` localised? It doesn't seem to be according to the help files. — thelatemail, Mar 03 '15 at 04:28
@Pascal, my local my PC is in Spanish ( i can get "ñ") but my RStudio is in English). Thus i get the names in english. — Omar Gonzales, Mar 03 '15 at 04:29
According to the help file at `?month.name` - try `format(ISOdate(2000, df$Mes, 1), "%B")` — thelatemail, Mar 03 '15 at 04:31
@thelatemail Correct, I mixed up with `strptime`. My comment is then obsolete. — , Mar 03 '15 at 04:31

A5C1D2H2I1M1N2O1R2T1 · Accepted Answer · 2015-03-03T04:37:42.550

3

The problem is that gsub(1, ...) would match the "1" in "1", "10", "11", and "12", unless you restrict it with "^" and "$" (for example, gsub("^1$", "Enero", Mes)) or unless you go from 12 to 1 in your long list of gsub code.

An easier approach might be to use factor or basic index-based matching.

Example:

set.seed(1)
Mes <- sample(12, 20, TRUE)

index <- c("Enero", "Febrero", "Marzo", "Abril", "Mayo", "Junio", "Julio", 
           "Agosto", "Setiembre", "Octubre", "Noviembre", "Diciembre")

index[Mes]
#  [1] "Abril"     "Mayo"      "Julio"     "Noviembre" "Marzo"     "Noviembre"
#  [7] "Diciembre" "Agosto"    "Agosto"    "Enero"     "Marzo"     "Marzo"    
# [13] "Setiembre" "Mayo"      "Octubre"   "Junio"     "Setiembre" "Diciembre"
# [19] "Mayo"      "Octubre"  
factor(Mes, levels = 1:12, labels = index)
#  [1] Abril     Mayo      Julio     Noviembre Marzo     Noviembre Diciembre Agosto   
#  [9] Agosto    Enero     Marzo     Marzo     Setiembre Mayo      Octubre   Junio    
# [17] Setiembre Diciembre Mayo      Octubre  
# 12 Levels: Enero Febrero Marzo Abril Mayo Junio Julio Agosto Setiembre ... Diciembre

edited Mar 03 '15 at 04:37

answered Mar 03 '15 at 04:31

A5C1D2H2I1M1N2O1R2T1

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The first answer to [this question](http://stackoverflow.com/questions/5869539/confusion-between-factor-levels-and-factor-labels) may be helpful for those who are not familiar with facotrs. – Jthorpe Mar 03 '15 at 04:33
Thanks, but with gsub I've tried this: `df$Mes – Omar Gonzales Mar 03 '15 at 04:37
@OmarGonzales, add quotes. – A5C1D2H2I1M1N2O1R2T1 Mar 03 '15 at 04:38
That specific error is because your regular expression is missing quotes. It should be: `df$Mes – Jthorpe Mar 03 '15 at 04:39
Got it. Thanks to both Ananda, @Jthorpe. – Omar Gonzales Mar 03 '15 at 04:40

R: gsub - Replace months (currently numbers to real names of months)

1 Answers1