sum two columns in R

Question

I feel a bit embarrassed as I am trying to add two columns in R to get the product   I have tried  sum col1 col2    but this returns  Error in Summary factor c 49L  48L  47L  46L  46L  45L  45L  44L  43L        sum not meaningful for factors   I thought this would very simple  both columns contain integers

User · Answer

You can use a for loop  for  i in 1 nrow df        df col3 i   lt - df col1 i    df col2 i

User · Answer

You can do this       df  lt - data frame  quot a quot    c 1 2 3 4    quot b quot    c 4 3 2 1    quot x ind quot    c 1 0 1 1    quot y ind quot    c 0 0 1 1    quot z ind quot    c 0 1 1 1    df   gt   mutate  bi    ifelse  df x ind   df y ind  df z ind    3  1 0

User · Answer

tablename column3 rowSums cbind tablename column1 tablename column2  na rm TRUE    This can be used to ignore blank values in the excel sheet  I have used for Euro stat dataset    This example works in R    crime stat data All theft  lt -rowSums cbind crime stat data Theft crime stat data Theft of a motorised land vehicle  crime stat data Burglary  crime stat data Burglary of private residential premises   na rm TRUE

User · Answer

Try this for creating a column3 as a sum of column1   column 2 in a table  tablename column3 rowSums cbind tablename column1 tablename column2

User · Answer

It could be that one or two of your columns may have a factor in them  or what is more likely is that your columns may be formatted as factors   Please would you give str col1  and str col2  a try   That should tell you what format those columns are in   I am unsure if you re trying to add the rows of a column to produce a new column or simply all of the numbers in both columns to get a single number

User · Answer

The sum function will add all numbers together to produce a single number  not a vector  well  at least not a vector of length greater than 1    It looks as though at least one of your columns is a factor  You could convert them into numeric vectors by checking this  head as numeric data col1      make sure this gives you the right output   And if that looks right  do  data col1  lt - as numeric data col1  data col2  lt - as numeric data col2    You might have to convert them into characters first  In which case do  data col1  lt - as numeric as character data col1   data col2  lt - as numeric as character data col2     It s hard to tell which you should do without being able to see your data   Once the columns are numeric  you just have to do  data col3  lt - data col1   data col2

[r] sum two columns in R

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