R/analysis.r
    adailyf.RdCalculate the the daily frequency. adailyf means 'analysis of the daily frequency'.
adailyf(mydata, datecol, if_plot = FALSE, col = "steelblue3", ylab = "Daily posts")
| mydata | A data frame with a date column. | 
|---|---|
| datecol | A chracter string of the date column name. The date column could either be Date or Character (in '%Y-%m-%d' format). | 
| if_plot | A logic value of whether plot the time series | 
| col | A color for plotting | 
| ylab | A character string of the y label | 
A dataframe of the daily frequency