Replace all particular values in a data frame

Question

Having a data frame  how do I go about replacing all particular values along all rows and columns  Say for example I want to replace all empty records with NA s  without typing the positions    df  lt - data frame list A c      xyz    jkl    B c 12      100         A   B 1      12 2  xyz     3  jkl 100   Expected result        A   B 1  NA   12 2  xyz  NA   3  jkl  100

User · Answer

Here are a couple dplyr options   library dplyr     all columns  df   gt      mutate all  na if            specific column types  df   gt      mutate if is factor   na if            specific columns    df   gt      mutate at vars A  B    na if            or  df   gt      mutate A   replace A  A        NA      replace can be used if you want something other than NA  df   gt      mutate A   as character A     gt      mutate A   replace A  A         used to be empty

User · Answer

We can use data table to get it quickly  First create df without factors   df  lt - data frame list A c     xyz   jkl    B c 12    100    stringsAsFactors F    Now you can use  setDT df  for  jj in 1 ncol df   set df  i   which df  jj         j   jj  v   NA    and you can convert it back to a data frame  setDF df    If you only want to use data frame and keep factors it s more difficult  you need to work with   levels df value  levels df value        lt - NA   where value is the name of every column  You need to insert it in a loop

User · Answer

Since PikkuKatja and glallen asked for a more general solution and I cannot comment yet  I ll write an answer  You can combine statements as in    gt  df df       df  12   lt - NA  gt  df      A    B 1   lt NA gt   lt NA gt  2  xyz   lt NA gt  3  jkl  100   For factors  zxzak s code already yields factors    gt  df  lt - data frame list A c     xyz   jkl    B c 12    100     gt  str df   data frame     3 obs  of  2 variables     A  Factor w  3 levels     jkl   xyz   1 3 2    B  Factor w  3 levels     100   12   3 1 2   If in trouble  I d suggest to temporarily drop the factors   df    lt - lapply df  as character

User · Answer

If you want to replace multiple values in a data frame  looping through all columns might help   Say you want to replace    and 100   na codes  lt - c 100      for  i in seq along df         df  i   df  i    in  na codes   lt - NA

User · Answer

Like this    gt  df df      lt -NA  gt  df      A    B 1  lt NA gt    12 2  xyz  lt NA gt  3  jkl  100

[r] Replace all particular values in a data frame

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