duplicateColumn (Compute)

When To Use

Use duplicateColumn when the same raw value must feed two different transformations or two different mapping fields. The compute inserts an exact copy of the column immediately after the original, so the copy sits at index column + 1 and every column that was to the right shifts one position right.

The canonical patterns are: duplicate a raw status column so one copy can be run through translate while the other is kept as human-readable status information, and duplicate a numeric column so one copy can be turned into a utilization ratio (divide, subtract) while the other keeps the absolute value.

Syntax

sources:
  batteryStatus:
    type: wmi
    namespace: root\cimv2
    query: SELECT BatteryStatus, DeviceID, EstimatedChargeRemaining, EstimatedRunTime, Status FROM Win32_Battery
    computes:
      # Duplicate Status to translate it
      # BatteryStatus;DeviceID;ChargeRemaining;RunTime;Status;Status;
    - type: duplicateColumn
      column: 5
    - type: translate
      column: 5
      translationTable: ${translation::BatteryStatusTranslationTable}

Properties

Table Transformation Example

With column: 2:

UsedMB, previously column 3, is now column 4.

Recommended Pattern

• Duplicate before destructive computes (translate, divide, substring, extractPropertyFromWbemPath) so the raw value survives for another mapping field.
• Immediately follow the duplication with a # Column1;Column2;... comment reflecting the new layout; the shifted indexes are the main source of errors.
• When several copies are needed, apply successive duplicateColumn computes and re-check indexes after each one (duplicating column 3 then column 5 in the new layout duplicates two different original columns).

Common Mistakes

• Continuing to address right-hand columns with their old indexes: everything after column shifted one position right.
• Assuming the copy replaces the original or lands at the end of the row: the original stays at column, the copy is inserted at column + 1.
• Forgetting that column is 1-based.

Community Examples

• Windows^[1]
• GenBatteryNT^[2]
• DiskPart^[3]

From Windows (duplicating the allocated pagefile size so one copy can be turned into free space), included directly from the connector source:

# Duplicate AllocatedBaseSize to calculate free space
# PageFileName;AllocatedBaseSizeMB;AllocatedBaseSizeMB;UsedMB
- type: duplicateColumn
  column: 2