How to avoid warning when introducing NAs by coercion

Question

I generally prefer to code R so that I don t get warnings  but I don t know how to avoid getting a warning when using as numeric to convert a character vector   For example   x  lt - as numeric c  1    2    X      Will give me a warning because it introduced NAs by coercion   I want NAs introduced by coercion - is there a way to tell it  yes this is what I want to do    Or should I just live with the warning   Or should I be using a different function for this task

User · Accepted Answer

Use suppressWarnings     suppressWarnings as numeric c  1    2    X      1   1  2 NA   This suppresses warnings

User · Answer

I have slightly modified the jangorecki function for the case where we may have a variety of values that cannot be converted to a number  In my function  a template search is performed and if the template is not found  FALSE is returned   before gperl  it means that we need those vector elements that do not match the template  The rest is similar to the as num function  Example  as num pattern  lt - function x  pattern     stopifnot is character x     na    grepl pattern  x    x na    -Inf   x   as numeric x    x na    NA real    x    as num pattern c  1    2    3 43    char1    test2    other3    23 40    23  54 cm       1  1 00 2 00 3 43   NA   NA   NA   NA   NA

User · Answer

suppressWarnings   has already been mentioned   An alternative is to manually convert the problematic characters to NA first   For your particular problem  taRifx  destring does just that   This way if you get some other  unexpected warning out of your function  it won t be suppressed    gt  library taRifx   gt  x  lt - as numeric c  1    2    X    Warning message  NAs introduced by coercion   gt  y  lt - destring c  1    2    X     gt  y  1   1  2 NA  gt  x  1   1  2 NA

User · Answer

In general suppressing warnings is not the best solution as you may want to be warned when some unexpected input will be provided  Solution below is wrapper for maintaining just NA during data type conversion  Doesn t require any package     as num   function x  na strings    NA         stopifnot is character x       na   x  in  na strings     x na    0     x   as numeric x      x na    NA real      x   as num c  1    2    X    na strings  X     1   1  2 NA

[r] How to avoid warning when introducing NAs by coercion

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