Appendix F. String and Date Function Reference

EViews provides a full library of string and date functions for use with alphanumeric and date values. Chapter 7, “Strings and Dates”, on page 119 contains a discussion of the use of strings and dates in EViews, and provides a description of the string and date functions.

The following is an alphabetical listing of the functions used when working with strings and dates in EViews.

Returns the date number given by d offset by offset time units as specified by the time unit string u. If no time unit is specified, EViews will use the workfile regular frequency, if available.

Example:

Suppose that the value of d is 730088.0 (midnight, December 1, 1999). Then we can add and subtract 10 days from the date by using the functions

@dateadd(730088.0, 10, "dd")

@dateadd(730088.0, -10, "dd")

which return 730098.0 (December 11, 1999) and (730078.0) (November 21, 1999). Note that these results could have been obtained by taking the original numeric value plus or minus 10.

To add 5 weeks to the existing date, simply specify “W” or “WW” as the time unit string:

@dateadd(730088.0, 5, "ww")

returns 730123.0 (January 5, 2000).

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Returns the difference between two date numbers d1 and d2, measured by time units specified by the time unit string u. If no time unit is specified, EViews will use the workfile regular frequency, if available.

Example:

Suppose that date1 is 730088.0 (December 1, 1999) and date2 is 729754.0 (January 1, 1999), then,

@datediff(730088.0, 729754.0, "dd")

returns 334 for the number of days between the two dates. Note that this is result is simply the difference between the two numbers.

The following expressions calculate differences in months and weeks:

@datediff(730088.0, 729754.0, "mm")

@datediff(730088.0, 729754.0, "ww")

return 11 and 47 for the number of months and weeks between the dates.

Finds the first possible date number associated with d1 in the given time unit u, with an optional step offset.

Example:

598—Appendix F. String and Date Function Reference

Convert the numeric date value, d, into a string representation of a date, str, using the optional format string fmt.

Example:

@datestr(730088,"mm/dd/yy")

will return “12/1/99”,

@datestr(730088,"DD/mm/yyyy")

will return “01/12/1999”, and

@datestr(730088,"Month dd, yyyy")

will return “December 1, 1999”, and

@datestr(730088,"w")

will produce the string “3”, representing the weekday number for December 1, 1999. See “Dates” on page 129 of the User’s Guide for additional details on date numbers and date format strings. See also @strdate (p. 607).

Convert the string representation of a date, str, into a date number using the optional format string fmt.

Example:

@dateval("12/1/1999", "mm/dd/yyyy")

will return the date number for December 1, 1999 (730088) while

@dateval("12/1/1999", "dd/mm/yyyy")

will return the date number for January 12, 1999 (729765).

See “Dates” on page 129 of the User’s Guide for additional details on date numbers and date format strings.