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- Function:
**LAG***(*¶`variable`[,`n`]) -
`variable`must be a numeric or string variable name.`LAG`

yields the value of that variable for the case`n`before the current one. Results in system-missing (for numeric variables) or blanks (for string variables) for the first`n`cases.`LAG`

obtains values from the cases that become the new active dataset after a procedure executes. Thus,`LAG`

will not return values from cases dropped by transformations such as`SELECT IF`

, and transformations like`COMPUTE`

that modify data will change the values returned by`LAG`

. These are both the case whether these transformations precede or follow the use of`LAG`

.If

`LAG`

is used before`TEMPORARY`

, then the values it returns are those in cases just before`TEMPORARY`

.`LAG`

may not be used after`TEMPORARY`

.If omitted,

`ncases`defaults to 1. Otherwise,`ncases`must be a small positive constant integer. There is no explicit limit, but use of a large value will increase memory consumption.

- Function:
**YRMODA***(*¶`year`,`month`,`day`) `year`is a year, either between 0 and 99 or at least 1582. Unlike other PSPP date functions, years between 0 and 99 always correspond to 1900 through 1999.`month`is a month between 1 and 13.`day`is a day between 0 and 31. A`day`of 0 refers to the last day of the previous month, and a`month`of 13 refers to the first month of the next year.`year`must be in range.`year`,`month`, and`day`must all be integers.`YRMODA`

results in the number of days between 15 Oct 1582 and the date specified, plus one. The date passed to`YRMODA`

must be on or after 15 Oct 1582. 15 Oct 1582 has a value of 1.

- Function:
*VALUELABEL***(**¶`variable`) Returns a string matching the label associated with the current value of

`variable`. If the current value of`variable`has no associated label, then this function returns the empty string.`variable`may be a numeric or string variable.