Plot Weekly or Monthly Totals in R

log.R

library(ggplot2)
library(scales)

# load data:
log <- data.frame(Date = c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2013/06/05","2013/06/07"), 
  Quantity = c(9,1,15,4,5,17,18))
log
str(log)

# convert date variable from factor to date format:
log$Date <- as.Date(log$Date,
  "%Y/%m/%d") # tabulate all the options here
str(log)

# create variables of the week and month of each observation:
log$Month <- as.Date(cut(log$Date,
  breaks = "month"))
log$Week <- as.Date(cut(log$Date,
  breaks = "week",
  start.on.monday = FALSE)) # changes weekly break point to Sunday
log

# graph by month:
ggplot(data = log,
  aes(Month, Quantity)) +
  stat_summary(fun.y = sum, # adds up all observations for the month
    geom = "bar") + # or "line"
  scale_x_date(
    labels = date_format("%Y-%m"),
    breaks = "1 month") # custom x-axis labels

# graph by week:
ggplot(data = log,
  aes(Week, Quantity)) +
  stat_summary(fun.y = sum, # adds up all observations for the week
    geom = "bar") + # or "line"
  scale_x_date(
    labels = date_format("%Y-%m-%d"),
    breaks = "1 week") # custom x-axis labels

Great way to show off cut(), but the 'scales' library isn't needed to scale the date. The ggplot scale_x_date() can be run with the date_labels argument.

ggplot(data = log, aes(Month, Quantity)) + stat_summary(fun.y = sum, geom = "bar") + scale_x_date(date_labels="%Y-%m", date_breaks = "1 month")

following code is giving error message as" Error in strsplit(unitspec, " ") : non-character argument" please tell me the solution

graph by month:

ggplot(data = log,
aes(Month, Quantity)) +
stat_summary(fun.y = sum, # adds up all observations for the month
geom = 'bar') + # or "line"
scale_x_date(
labels = date_format('%Y-%m'),
breaks = "1 month") # custom x-axis labels

@Dhanashree2491 - a quick google search turned up:
https://stackoverflow.com/questions/32653730/ggplot2-scale-x-date

In a nutshell, you must change "breaks" to "date_breaks" in the last line of code you pasted

Thank you for the nice examples!! Is there any way to remove grid bw background and modify the dates on the x-axis to mm/dd/yyyy format?