How can a add a row to a data frame in R

Question

In R  how do you add a new row to a data frame once the data frame has already been initialized   So far I have this   df  lt - data frame  hi    bye   names df   lt - c  hello    goodbye     I am trying to add  hola  and  ciao  as a new row de  lt - data frame  hola    ciao    merge df  de    Adds to the same row as new columns    Unfortunately  I couldn t find an rbind   solution that wouldn t give me an error   Any help would be appreciated

User · Answer

I like list instead of c because it handles mixed data types better   Adding an additional column to the original poster s question    Create an empty data frame df  lt - data frame hello character    goodbye character    volume double    de  lt - list hello  hi   goodbye  bye   volume 3 0  df   rbind df de  stringsAsFactors FALSE  de  lt - list hello  hola   goodbye  ciao   volume 13 1  df   rbind df de  stringsAsFactors FALSE    Note that some additional control is required if the string factor conversion is important   Or using the original variables with the solution from MatheusAraujo Ytsen de Boer   df nrow df    1     list hello  hallo  goodbye  auf wiedersehen   volume 20 2    Note that this solution doesn t work well with the strings unless there is existing data in the dataframe

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If you want to make an empty data frame and add contents in a loop  the following may help     Number of students in class student count  lt - 36    Gather data about the students student age  lt - sample 14 17  size   student count  replace   TRUE  student gender  lt - sample c  male    female    size   student count  replace   TRUE  student marks  lt - sample 46 97  size   student count  replace   TRUE     Create empty data frame student data  lt - data frame      Populate the data frame using a for loop for  i in 1   student count          Get the row data     age  lt - student age i      gender  lt - student gender i      marks  lt - student marks i         Populate the row     new row  lt - data frame age   age  gender   gender  marks   marks         Add the row     student data  lt - rbind student data  new row       Print the data frame student data   Hope it helps

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I need to add stringsAsFactors FALSE when creating the dataframe    gt  df  lt - data frame  hello   character 0    goodbye  character 0    gt  df  1  hello   goodbye  lt 0 rows gt   or 0-length row names   gt  df nrow df    1     list  hi   bye   Warning messages  1  In    lt - factor    tmp    iseq  value    hi       invalid factor level  NA generated 2  In    lt - factor    tmp    iseq  value    bye       invalid factor level  NA generated  gt  df   hello goodbye 1   lt NA gt      lt NA gt   gt         gt  df  lt - data frame  hello   character 0    goodbye  character 0   stringsAsFactors FALSE   gt  df  1  hello   goodbye  lt 0 rows gt   or 0-length row names   gt  df nrow df    1     list  hi   bye    gt  df nrow df    1     list  hola   ciao    gt  df nrow df    1     list hello  hallo  goodbye  auf wiedersehen    gt  df   hello         goodbye 1    hi             bye 2  hola            ciao 3 hallo auf wiedersehen  gt

User · Answer

Like  Khashaa and  Richard Scriven point out in comments  you have to set consistent column names for all the data frames you want to append    Hence  you need to explicitly declare the columns names for the second data frame  de  then use rbind    You only set column names for the first data frame  df   df lt -data frame  hi   bye   names df  lt -c  hello   goodbye    de lt -data frame  hola   ciao   names de  lt -c  hello   goodbye    newdf  lt - rbind df  de

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There s now add row   from the tibble or tidyverse packages   library tidyverse  df   gt   add row hello    hola   goodbye    ciao     Unspecified columns get an NA

User · Answer

Or  as inspired by  MatheusAraujo   df nrow df    1     list  v1   v2    This would allow for mixed data types

User · Answer

Not terribly elegant  but   data frame rbind as matrix df   as matrix de      From documentation of the rbind function      For rbind column names are taken from the first argument with appropriate names  colnames for a matrix

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To formalize what someone else used setNames for  add row  lt - function original data  new vals list        appends row to dataset while assuming new vals are ordered and classed appropriately       new vals must be a list not a single vector     rbind      original data      setNames data frame new vals list   colnames original data              It preserves class when legal and passes errors elsewhere  m  lt - mtcars   1 3  m cyl  lt - as factor m cyl  str m     data frame    32 obs  of  3 variables      mpg   num  21 21 22 8 21 4 18 7 18 1 14 3 24 4 22 8 19 2         cyl   Factor w  3 levels  quot 4 quot   quot 6 quot   quot 8 quot   2 2 1 2 3 2 3 1 1 2         disp  num  160 160 108 258 360      Factor preserved when adding 4  even though it was passed as a numeric  str add row m  list 20 4 160      data frame    33 obs  of  3 variables      mpg   num  21 21 22 8 21 4 18 7 18 1 14 3 24 4 22 8 19 2         cyl   Factor w  3 levels  quot 4 quot   quot 6 quot   quot 8 quot   2 2 1 2 3 2 3 1 1 2          disp  num  160 160 108 258 360       Attempting to pass a non- 4 6 8 would return an error that factor level is invalid  str add row m  list 20 3 160       data frame   33 obs  of  3 variables      mpg   num  21 21 22 8 21 4 18 7 18 1 14 3 24 4 22 8 19 2         cyl   Factor w  3 levels  quot 4 quot   quot 6 quot   quot 8 quot   2 2 1 2 3 2 3 1 1 2         disp  num  160 160 108 258 360     Warning message  In    lt - factor    tmp    ri  value   3      invalid factor level  NA generated

User · Answer

Let s make it simple   df nrow df    1     c  v1   v2

User · Answer

There is a simpler way to append a record from one dataframe to another IF you know that the two dataframes share the same columns and types   To append one row from xx to yy just do the following where i is the i th row in xx   yy nrow yy  1    lt - xx i     Simple as that   No messy binds   If you need to append all of xx to yy  then either call a loop or take advantage of R s sequence abilities and do this   zz  nrow zz  1   nrow zz  nrow yy      lt - yy 1 nrow yy

User · Answer

Make certain to specify stringsAsFactors FALSE when creating the dataframe    gt  rm list ls     gt  trigonometry  lt - data frame character 0   numeric 0   stringsAsFactors FALSE   gt  colnames trigonometry   lt - c  theta    sin theta    gt  trigonometry  1  theta     sin theta  lt 0 rows gt   or 0-length row names   gt  trigonometry nrow trigonometry    1     lt - c  0   sin 0    gt  trigonometry nrow trigonometry    1     lt - c  pi 2   sin pi 2    gt  trigonometry   theta sin theta 1     0         0 2  pi 2         1  gt  typeof trigonometry   1   list   gt  class trigonometry   1   data frame    Failing to use stringsAsFactors FALSE when creating the dataframe will result in the following error when attempting to add the new row    gt  trigonometry nrow trigonometry    1     lt - c  0   sin 0   Warning message  In    lt - factor    tmp    iseq  value    0       invalid factor level  NA generated

[r] How can a add a row to a data frame in R?

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