Right way to convert data frame to a numeric matrix when df also contains strings

Question

I have a data frame taken from a  csv-file which contains numeric and character values  I want to convert this data frame into a matrix  All containing information is numbers  the non-number-rows I deleted   so it should be possible to convert the data frame into a numeric matrix  However  I do get a character matrix   I found the only way to solve this is to use as numeric for each and every row  but this is quite time-consuming  I am quite sure there is a way to do this with some kind of if i in 1 n -form  but I cannot figure out how it might work  Or is the only way really to already start with numeric values  like proposed here Making matrix numeric and name orders    Probably this is a very easy thing for most of you  P  The matrix is a lot bigger  this is only the first few rows    Here s the code    cbind  as numeric SFI Matrix   1    as numeric SFI Matrix   2    as numeric SFI Matrix   3    as numeric SFI Matrix   4    as numeric SFI Matrix   5    as numeric SFI Matrix   6         to get something like this again   Social Assistance Danger Poverty GINI S80S20 Low Edu        Unemployment  0 147             0 125          0 34    5 5   0 149        0 135 0 18683691 0 258             0 229          0 27    3 8   0 211        0 175 0 22329362 0 207             0 119          0 22    3 1   0 139        0 163 0 07170422 0 219             0 166          0 25    3 6   0 114        0 163 0 03638525 0 278             0 218          0 29    4 1   0 270        0 198 0 27407825 0 288             0 204          0 26    3 6   0 303        0 211 0 22372633   Thank you for any help

User · Answer

Here is an alternative way if the data frame just contains numbers.

_x000D_

apply(as.matrix.noquote(SFI),2,as.numeric)

_x000D_

but the most reliable way of converting a data frame to a matrix is using data.matrix() function.

User · Answer

I manually filled NAs by exporting the CSV then editing it and reimporting  as below   Perhaps one of you experts might explain why this procedure worked so well   the first file had columns with data of types char  INT and num  floating point numbers    which all became char type after STEP 1  but at the end of STEP 3 R correctly recognized the datatype of each column      STEP 1  MainOptionFile  lt - read csv  XLUopt XLUstk v3 csv                               header T  stringsAsFactors FALSE       STEP 2  TestFrame  lt - subset MainOptionFile  str locate option symbol  120616P00034000    gt  0  write csv TestFrame  file    TestFrame2 csv           STEP 3    I made various amendments to  TestFrame2 csv   including replacing all missing data cells with appropriate numbers  I then read that amended data frame back into R as follows      XLU 34P 16Jun12  lt - read csv  TestFrame2 v2 csv                               header T stringsAsFactors FALSE    On arrival back in R  all columns had their correct measurement levels automatically recognized by R

User · Answer

I had the same problem and I solved it like this  by taking the original data frame without row names and adding them later  SFIo  lt - as matrix apply SFI  -1  2 as numeric   row names SFIo   lt - SFI  1

User · Answer

Another way of doing it is by using the read table   argument colClasses to specify the column type by making colClasses c  column class types     If there are 6 columns whose members you want as numeric  you need to repeat the character string  numeric  six times separated by commas  importing the data frame  and as matrix   the data frame   P S  looks like you have headers  so I put header T   as matrix read table SFI matrix header T  colClasses c  numeric   numeric   numeric   numeric   numeric   numeric    sep

User · Answer

data matrix SFI    From  data matrix   Description    Return the matrix obtained by converting all the variables in a  data frame to numeric mode and then binding them together as the  columns of a matrix   Factors and ordered factors are replaced by  their internal codes

User · Answer

Edit 2   See  flodel s answer    Much better    Try      assuming SFI is your data frame as matrix sapply SFI  as numeric       Edit   or as   CarlWitthoft suggested in the comments    matrix as numeric unlist SFI   nrow nrow SFI

[r] Right way to convert data.frame to a numeric matrix, when df also contains strings?

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