I continue to receive an error code: There were 50 or more warnings (use warnings() to see the first 50)

[tamekawomack]

mean_growth = by (chickwts$feed, chickwts$weight, mean)
There were 50 or more warnings (use warnings() to see the first 50)

mean_growth=by(chickwts$feed, chickwts$weight, mean)
There were 50 or more warnings (use warnings() to see the first 50)
sd_growth =by (chickwts$feed, chickwts$weight, sd)
Error in var(if (is.vector(x) || is.factor(x)) x else as.double(x), na.rm = na.rm) :
Calling var(x) on a factor x is defunct.
Use something like 'all(duplicated(x)[-1L])' to test for a constant vector.
(warn=1) mean_growth=by (chickwts$feed,chickwts$weight, mean)
Error: unexpected symbol in "(warn=1) mean_growth"
warn =1, mean_growth =by (chickwts$feed,chickwts$weight,mean)
Error: unexpected ',' in "warn =1,"
warn=1 mean_growth = by)chickwts$feed,chickwts$weight,mean)
Error: unexpected symbol in "warn=1 mean_growth"

[technocrat]

See the FAQ: How to do a minimal reproducible example reprex for beginners for a better way to pose questions. Fortunately the chickwts dataset is a built-in.

by(chickwts[, 1], chickwts[,"feed"], mean)
#> chickwts[, "feed"]: casein
#> [1] 323.5833
#> ------------------------------------------------------------ 
#> chickwts[, "feed"]: horsebean
#> [1] 160.2
#> ------------------------------------------------------------ 
#> chickwts[, "feed"]: linseed
#> [1] 218.75
#> ------------------------------------------------------------ 
#> chickwts[, "feed"]: meatmeal
#> [1] 276.9091
#> ------------------------------------------------------------ 
#> chickwts[, "feed"]: soybean
#> [1] 246.4286
#> ------------------------------------------------------------ 
#> chickwts[, "feed"]: sunflower
#> [1] 328.9167