Converting Factor to Date without creating NA's - r

Question

I'm running into problems converting factor to date; it is making NA values which I don't want.
Data for my problem can be found here: (https://d396qusza40orc.cloudfront.net/repdata%2Fdata%2Factivity.zip)
x <- read.csv("activity.csv")
head(x)
steps date interval
1 NA 2012-10-01 0
2 NA 2012-10-01 5
3 NA 2012-10-01 10
4 NA 2012-10-01 15
5 NA 2012-10-01 20
6 NA 2012-10-01 25
Goal: I'm trying to find the mean total number of steps taken per day. So first, I need to bin values so that each data point corresponds to the sum for a given day
x$Day <- as.Date(cut(x$date, breaks = "day"))
Error in cut.default(x$date, breaks = "day") : 'x' must be numeric
Just confirm this with class function
class(x[,2])
"factor"
This is weird because from the head(x) above it looked like it was Date. Anyways so in order to bin values so that each data point corresponds to the sum for a given day using the cut function I need to change the date's to "Date" class
x[,2] <- as.Date(x[,2], format="%Y/%m/%d")
class(x[,2])
[1] "Date"
OK, so in theory I should be able to bin values now
x$Day <- as.Date(cut(x$date, breaks = "day"))
Error in seq.int(0, to0 - from, by) : 'to' cannot be NA, NaN or infinite
In addition: Warning messages:
1: In min.default(c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, :
no non-missing arguments to min; returning Inf
2: In max.default(c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, :
no non-missing arguments to max; returning -Inf
head(is.na(x))
steps date interval
[1,] TRUE TRUE FALSE
[2,] TRUE TRUE FALSE
[3,] TRUE TRUE FALSE
[4,] TRUE TRUE FALSE
[5,] TRUE TRUE FALSE
[6,] TRUE TRUE FALSE
If I compare this to what I saw prior to the x[,2] <- as.Date(x[,2], format="%Y/%m/%d")
head(is.na(x))
steps date interval
[1,] TRUE FALSE FALSE
[2,] TRUE FALSE FALSE
[3,] TRUE FALSE FALSE
[4,] TRUE FALSE FALSE
[5,] TRUE FALSE FALSE
[6,] TRUE FALSE FALSE
Not sure what's going on here? I know this should work because I got this idea from the following tutorial (http://blog.mollietaylor.com/2013/08/plot-weekly-or-monthly-totals-in-r.html?m=1)
sessionInfo()
R version 3.0.3 (2014-03-06)
Platform: x86_64-w64-mingw32/x64 (64-bit)
locale:
[1] LC_COLLATE=English_Canada.1252
[2] LC_CTYPE=English_Canada.1252
[3] LC_MONETARY=English_Canada.1252
[4] LC_NUMERIC=C
[5] LC_TIME=English_Canada.1252
attached base packages:
[1] stats graphics grDevices utils
[5] datasets methods base
other attached packages:
[1] scales_0.2.4 ggplot2_1.0.0
loaded via a namespace (and not attached):
[1] colorspace_1.2-4 digest_0.6.4
[3] grid_3.0.3 gtable_0.1.2
[5] MASS_7.3-29 munsell_0.4.2
[7] plyr_1.8.1 proto_0.3-10
[9] Rcpp_0.11.1 reshape2_1.4
[11] stringr_0.6.2 tools_3.0.3

Answer 1

Just to illustrate, these all result in the same output (except for the class of the date column of course):
x <- read.csv("~/Downloads/activity.csv")
# Date is a factor
r1 <- aggregate(steps~date,data = x,FUN = mean)
x1 <- read.csv("~/Downloads/activity.csv",stringsAsFactors = FALSE)
# Date is a character
r2 <- aggregate(steps~date,data = x1,FUN = mean)
x2 <- x
x2$date <- as.Date(as.character(x$date))
# Date is a date
r3 <- aggregate(steps~date,data = x2,FUN = mean)

Answer 2

my_data <-
read.csv(your_file, stringsAsFactors = FALSE)
# Convert 'my_data$date' to Date format
my_data$date <-
as.Date(my_data$date)
This should work...