Let's discuss why an "object not found" error can be thrown in R in addition to explaining what it means. What it means (to many) is obvious: the variable in question, at least according to the R interpreter, has not yet been defined, but if you see your object in your code there can be multiple reasons for why this is happening:
check syntax of your declarations. If you mis-typed even one letter or used upper case instead of lower case in a later calling statement, then it won't match your original declaration and this error will occur.
Are you getting this error in a notebook or markdown document? You may simply need to re-run an earlier cell that has your declarations before running the current cell where you are calling the variable.
Are you trying to knit your R document and the variable works find when you run the cells but not when you knit the cells? If so - then you want to examine the snippet I am providing below for a possible side effect that triggers this error:
{r sourceDataProb1, echo=F, eval=F}
# some code here
The above snippet is from the beginning of an R markdown cell. If eval and echo are both set to False this can trigger an error when you try to knit the document. To clarify. I had a use case where I had left these flags as False because I thought i did not want my code echoed or its results to show in the markdown HTML I was generating. But since the variable was then used in later cells, this caused an error during knitting. Simple trial and error with T/F TRUE/FALSE flags can establish if this is the source of your error when it occurs in knitting an R markdown document from RStudio.
Lastly: did you remove the variable or clear it from memory after declaring it?
The error means that R could not find the variable mentioned in the error message.
The easiest way to reproduce the error is to type the name of a variable that doesn't exist. (If you've defined x already, use a different variable name.)
x
## Error: object 'x' not found
The more complex version of the error has the same cause: calling a function when x does not exist.
mean(x)
## Error in mean(x) :
## error in evaluating the argument 'x' in selecting a method for function 'mean': Error: object 'x' not found
Once the variable has been defined, the error will not occur.
x <- 1:5
x
## [1] 1 2 3 4 5
mean(x)
## [1] 3
You can check to see if a variable exists using ls or exists.
ls() # lists all the variables that have been defined
exists("x") # returns TRUE or FALSE, depending upon whether x has been defined.
Errors like this can occur when you are using non-standard evaluation. For example, when using subset, the error will occur if a column name is not present in the data frame to subset.
d <- data.frame(a = rnorm(5))
subset(d, b > 0)
## Error in eval(expr, envir, enclos) : object 'b' not found
The error can also occur if you use custom evaluation.
get("var", "package:stats") #returns the var function
get("var", "package:utils")
## Error in get("var", "package:utils") : object 'var' not found
In the second case, the var function cannot be found when R looks in the utils package's environment because utils is further down the search list than stats.
In more advanced use cases, you may wish to read:
I had a similar problem with R-studio. When I tried to do my plots, this message was showing up.
Eventually I realised that the reason behind this was that my "window" for the plots was too small, and I had to make it bigger to "fit" all the plots inside!
Hope to help
While executing multiple lines of code in R, you need to first select all the lines of code and then click on "Run". This error usually comes up when we don't select our statements and click on "Run".
Source: Stackoverflow.com