Variation of the number of documents in the corpus over time, possibly grouped by variable.
This dialog allows computing and plotting the number of documents over a time variable.
The format used by the chosen time variable has to be specified so that it is handled
correctly. The format codes allowed are those recognized by strptime
(see ?strptime), in particular:
Abbreviated weekday name in the current locale. (Also matches full name.)
Full weekday name in the current locale. (Also matches abbreviated name.)
Abbreviated month name in the current locale. (Also matches full name.)
Full month name in the current locale. (Also matches abbreviated name.)
Day of the month as decimal number (01-31).
Hours as decimal number (00-23).
Hours as decimal number (01-12).
Month as decimal number (01-12).
Minute as decimal number (00-59).
Week of the year as decimal number (00-53) using Sunday as the first day 1 of the week (and typically with the first Sunday of the year as day 1 of week 1). The US convention.
Week of the year as decimal number (00-53) using Monday as the first day 1 of the week (and typically with the first Monday of the year as day 1 of week 1). The UK convention.
AM/PM indicator in the locale. Used in conjunction with ‘%I’ and not with ‘%H’.
Second as decimal number (00-61).
Year without century (00-99).
Year with century.
“Time units” are chosen automatically according to the values of the time variable: it is set to the smallest unit in which all time values can be uniquely expressed. For example, if free dates are entered, the unit will be days; if times are entered but minutes are always 0, hours will be used; finally, if times are fully specified, seconds will be used as the time unit. The chosen unit appears in the vertical axis label of the plot.
The rolling mean is left-aligned, meaning that the number of documents reported for a
point reflects the average of the values of the points occurring after it. When percents
of documents are plotted, time units with no document in the corpus are not plotted, since they
have no defined value (0/0, reported as NaN); when a rolling mean is applied, the values
are simply ignored, i.e. the mean is computed over the chosen window without the missing points.
setCorpusVariables, meta, zoo, xyplot,
varTimeSeriesDlg, recodeTimeVarDlg