replace (Compute)

When To Use

Use replace to substitute every occurrence of a specific string in a column with another value, on every row of the table. Typical uses are cleanup — stripping quotes from CSV-style output (existingValue: '"', newValue: ""), removing spaces, collapsing doubled backslashes in WMI paths — and neutralizing sentinel values (e.g. replacing 4294967295 with 0, or an invalid reading with an empty string so mapping ignores it).

Both existingValue and newValue accept $n column references, which enables conditional-style column fills: replace the whole content of a column (existingValue: $7) with the content of another column (newValue: $19).

Syntax

sources:
  virtualMachines:
    type: commandLine
    commandLine: powershell -command "Get-VM | ForEach-Object { ... }"
    computes:
      # Remove the double quotes around the VM name
    - type: replace
      column: 1
      existingValue: '"'
      newValue: ""

Properties

Table Transformation Example

With column: 1, existingValue: '"', and newValue: "":

Recommended Pattern

• Chain several replace computes for multi-step cleanup; they run in order, so a first pass can replace a placeholder (MSHWMSHW → $2) and a second pass can remove what remains (MSHW → "").
• Use existingValue: $n with the same column: n to overwrite the entire column with newValue — a common way to copy another column (newValue: $19) into place.
• Replace sentinel values (4294967295, 71582788) with 0 or "" before mapping interprets them as real measurements.
• Quote YAML-sensitive values: existingValue: '"', newValue: "".

Common Mistakes

• Expecting regex semantics: existingValue is a plain string. Use awk or extract for pattern-based transformations.
• Forgetting that all occurrences in the cell are replaced, not just the first one or exact whole-cell matches.
• Forgetting that column is 1-based.
• Writing newValue: $2 expecting a literal $2: $n is interpreted as a column reference.

Community Examples

• HyperV^[1]
• MIB2^[2]
• GenBatteryNT^[3]

From MIB2 (filling a blank placeholder column from another column), included directly from the connector source:

  # Replace "MSHWMSHW", i.e. a blank column with the ifTable value.
  # PortID;Description;PortType;MacAddress;AdminStatus;ID;Name;Alias;
- type: replace
  column: 7
  existingValue: MSHWMSHW
  newValue: $2