Delete character-columns item – D

You can use the Delete-characters command to delete data from specific column locations within the result string.

Syntax of a delete character-columns item:


D   column-reference


D:

       Introduces the delete character-columns item


Column-reference:


Specifies columns in the result string to be deleted.  The column reference cannot be omitted.  If you leave out the column reference, it will not select the entire result string for deletion, but will issue an error message.  You are not prevented from intentionally deleting the entire result string by specifying an explicit column reference such as D1+ though generally such a command would serve no purpose.


Note that if you perform several D commands in the same mapping string, the relative column numbers to the right of where you delete data within the result string will change with each D command.  To simplify this and avoid problems, do such multiple deletes in a right-to-left manner.


For example, suppose your result string contained "Abc/Def/Xyz", where the / slash characters are in positions 4 and 8. and you were trying to delete both slashes.  If your mapping string contained "D4 D8", you would first delete the / slash in position 4, leaving the result string at that point with the value "AbcDef/Xyz".  However, if the D8 command is then performed, the second / slash is no longer in position 8 but in 7, and the X is in 8), so that D8 will delete the X rather than the second slash, giving you a final result of "AbcDef/yz".


By switching the two commands, a mapping string of "D8 D4" will delete both slashes the right way in the right order, leaving you with "AbcDefXyz".


For similar reasons, if you were going to delete the two slashes in this same data, using end-relative notation, you would do so with a mapping command of "D8* D4*".


If you are interested in deleting specific kinds of characters, and not just at certain locations, you can use the Delete Character values command, described next.




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