Packed Dates¶
Dates of the form YYYYMMDD may be packed into five characters to conserve space.
The first two digits of the year are packed into a single character in column 1 (I = 18, J = 19, K = 20). Columns 2-3 contain the last two digits of the year. Column 4 contains the month and column 5 contains the day, coded as detailed below:
Month Day Character Day Character
in Col 4 or 5 in Col 4 or 5
Jan. 1 1 17 H
Feb. 2 2 18 I
Mar. 3 3 19 J
Apr. 4 4 20 K
May 5 5 21 L
June 6 6 22 M
July 7 7 23 N
Aug. 8 8 24 O
Sept. 9 9 25 P
Oct. 10 A 26 Q
Nov. 11 B 27 R
Dec. 12 C 28 S
13 D 29 T
14 E 30 U
15 F 31 V
16 G
Examples:
1996 Jan. 1 = J9611
1996 Jan. 10 = J961A
1996 Sept.30 = J969U
1996 Oct. 1 = J96A1
2001 Oct. 22 = K01AM
This system can be extended to dates with non-integral days. The decimal fraction of the day is simply appended to the five characters defined above.
Examples: