Error in ncol(xj) : object 'xj' not found using rowSums

问题

I'm using R and rowSums function for a data frame as discussed in this post: Sum over spatialGridDataFrame: rowSums or colSums. Now suing rowSums as follows:

FLintMod[[2+nsim]] <- rowSums(FLintMod@data[, 2:(1+nsim)], na.rm=TRUE)

Now I'm facing new error and I really don't have any idea why I'm getting this error:

Error in ncol(xj) : object 'xj' not found

Could you please help me understand this problem and solve it.

For your information, this code worked before but after improving code and specially doing the following work to return raster to spatial grid data frame I got this error:

FLintRaster <- raster(FLint[i+1])
FLintRasterMod <- mask(FLintRaster, FloodExtent)
FLintMod[[i+1]] <- as(FLintRasterMod,"SpatialGridDataFrame")@data 

Best,

回答1:

I finally found my answer. I generated data frame @ data frame! In oredr to return raster to data frame I should use as.vector() function.

FLintRaster <- raster(FLint[i+1])
FLintRasterMod <- mask(FLintRaster, FloodExtent)   
FLintMod[[i+1]] <- as.vector(FLintRasterMod, mode='any')

I'll be happy if someone can explain more technically what happened in my case. I'm very new to R and eager to learn the basics of that.

Best,

来源：https://stackoverflow.com/questions/45122894/error-in-ncolxj-object-xj-not-found-using-rowsums