---
title: "Look Up Value"
url: "https://help.flows.world/en/article/look-up-value"
language: "en"
last_updated: "2026-09-19T07:50:32.369Z"
---

# Look Up Value

## Overview

**Look Up Value** performs data mapping by searching for an input value in a lookup table and returning the corresponding output value. Use this stage for data transformation, categorization, and value mapping in flows.

When the input value matches a key in the lookup table, the corresponding value is returned. If no match is found, the default value is used instead.

![](https://cdn-assets.productfruits.com/b45aa032-859c-4bfc-8af7-6c2370931d7d)

\* Example flow demonstrating how **Look Up Value** maps a deposit status to a corresponding value and makes the result available for use in the next stage.

**Note:** The variable names, values, criteria, and configuration used in this example are for demonstration purposes only.

**Where to find it:** *Actions > Transformers* in the stage library.

## Configuration

### Required Fields

| Field | Description | Example |
| --- | --- | --- |
| **Input variable** | The value to look up in the lookup table | `{{status}}`, `{{productCode}}` |
| **Default if not found** | Value returned if no matching key found | `Unknown`, `={{defaultValue}}` |
| **Output value** | Variable name to store the result | `statusDescription`, `category` |
| **Lookup Table** | Key-value pairs mapping inputs to outputs | `1` → `Pending`, `2` → `Processing` |

**Using functions in these fields:** Any value field above accepts `@` functions, for example `@NowSecond` for the current time or `@calc(...)` for a calculation. 

See [Flows Functions](https://help.flows.world/en/article/flows-functions) for the full list.

## Exit Points

| Exit | When | Output Variable |
| --- | --- | --- |
| **Pass** | Input key matches a key in lookup table | Contains matched value (or evaluated expression) |
| **Fail** | Input key does NOT match any key in lookup table | Contains default value |

## How It Works

When executed, the stage:

1.  **Resolves input value** - Evaluates the input variable from flow
2.  **Searches lookup table** - Compares input against each key (case-sensitive, exact match)
3.  **Returns matched value** - If match found, returns corresponding value (evaluates expressions starting with =)
4.  **Uses default if not found** - If no match, returns default value
5.  **Routes to appropriate exit** - Pass if matched, Fail if using default

## Lookup Table Structure

| Key (Input to Match) | Value (Output to Return) | Supports |
| --- | --- | --- |
| Exact match string | Static value or expression | Text, numbers, codes |
| Case-sensitive | Expressions starting with = | Math calculations |

## Common Use Cases

### 1\. Order Status Mapping

Map numeric status codes to user-friendly descriptions.

**Configuration:**

-   **Input variable:** `{{orderStatus}}`
-   **Default:** `Unknown Status`
-   **Output value:** `statusDescription`
-   **Lookup Table:**
    -   `1` → `Pending`
    -   `2` → `Processing`
    -   `3` → `Shipped`
    -   `4` → `Delivered`
    -   `5` → `Returned`

**Result:**

-   If `{{orderStatus}}` = "2" → Pass exit, `{{statusDescription}}` = "Processing"
-   If `{{orderStatus}}` = "99" → Fail exit, `{{statusDescription}}` = "Unknown Status"

### 2\. Product Category Lookup

Map product IDs to category names.

**Configuration:**

-   **Input variable:** `{{product.id}}`
-   **Default:** `Uncategorized`
-   **Output value:** `category`
-   **Lookup Table:**
    -   `PROD001` → `Electronics`
    -   `PROD002` → `Clothing`
    -   `PROD003` → `Food`
    -   `PROD004` → `Books`

### 3\. Region to Tax Rate Lookup

Map regions to tax rates using mathematical expressions.

**Configuration:**

-   **Input variable:** `{{shippingRegion}}`
-   **Default:** `0.07`
-   **Output value:** `taxRate`
-   **Lookup Table:**
    -   `CA` → `=0.0725`
    -   `TX` → `=0.0625`
    -   `NY` → `=0.08`
    -   `FL` → `=0`

**Then use in calculation:** `{{orderTotal}} * {{taxRate}}`

### 4\. Currency Code to Symbol

Convert currency codes to display symbols.

**Lookup Table:**

-   `USD` → `$`
-   `EUR` → `€`
-   `GBP` → `£`
-   `JPY` → `¥`

## Expression Support

A matched value starting with `=` is evaluated as a math expression (arithmetic and math functions, no conditional logic). This applies to the values in the lookup table only. the default value is returned as-is and is not evaluated, so keep it a plain value.

| Value | Interpretation | Result |
| --- | --- | --- |
| `=0.0725` | Math expression | "0.0725" (string) |
| `=10 + 5` | Math expression | "15" (string) |
| `Text Value` | Static text | "Text Value" (string) |

## Key Behaviors

| Feature | Behavior |
| --- | --- |
| **Case Sensitivity** | "CA" and "ca" are different keys (exact match required) |
| **Exit Routing** | ✓ Pass = Match found, Fail = Default used |
| **Expression Evaluation** | ✓ Values starting with = evaluated as math expressions |
| **Default Value** | ✓ Always returns a value (match or default) |
| **First Match** | ✓ Stops at first matching key (order matters if duplicates exist) |

## Best Practices

-   ✓ Use meaningful default values that indicate "not found" clearly
-   ✓ Keep keys consistent in format (all uppercase or all lowercase)
-   ✓ Use Pass/Fail exits to handle matched vs unmatched cases differently
-   ✓ Test with both matching and non-matching inputs
-   ✓ Use expressions (=) for numeric lookups when calculations needed
-   ✓ Document your lookup tables in flow comments
-   ✓ Consider using Query Data stage for very large lookup tables stored in database

## Common Mistakes

| Mistake | Symptom | Fix |
| --- | --- | --- |
| Case mismatch | Expected match not found, uses default | Ensure keys match exactly including case ("CA" ≠ "ca") |
| Expecting Fail for match | Wrong exit path taken | Pass = match found, Fail = default used (not error) |
| Forgetting = for expressions | Expression treated as text instead of being evaluated | Start values with = for math: `=0.0725` not `0.0725` |
| Using same key multiple times | Only first match used | Ensure unique keys; first matching key wins |
| Not handling Fail exit | Flow breaks when no match found | Connect Fail exit to handle unmatched cases |

## Troubleshooting

| Issue | Exit/Result | Common Cause | Fix |
| --- | --- | --- | --- |
| Always using default value | Fail (default used) | Keys don't match exactly (case, whitespace, type) | Verify exact match including case; check for extra spaces |
| Expression not evaluating | Pass/Fail (but wrong value) | Missing = prefix for expression | Start value with =: `=10+5` not `10+5` |
| Wrong value returned | Pass (but unexpected value) | Duplicate keys, first match used | Remove duplicate keys; ensure each key is unique |
| Flow breaks on no match | Fail (but no handler) | Fail exit not connected | Connect Fail exit to handle default case |

## Do's and Don'ts

### Do:

-   ✓ Use meaningful default values
-   ✓ Keep keys consistent in format
-   ✓ Test with both matching and non-matching inputs
-   ✓ Use expressions for numeric calculations
-   ✓ Connect both Pass and Fail exits
-   ✓ Document lookup tables in comments

### Don't:

-   ✗ Mix case in keys (inconsistent uppercase/lowercase)
-   ✗ Expect Fail exit to mean error (it means "no match")
-   ✗ Forget = prefix for expressions
-   ✗ Use duplicate keys (only first matches)
-   ✗ Leave Fail exit unconnected

## Related Stages

-   [**Route Flow**](https://help.flows.world/en/article/route-flow)**:** For more complex conditional logic beyond simple lookups
-   [**Query Data**](https://help.flows.world/en/article/query-data)**:** For lookups from database tables instead of hardcoded values
-   [**Change Data**](https://help.flows.world/en/article/change-data)**:** For simple value assignments without lookup logic
-   [**Set Default Value**](https://help.flows.world/en/article/set-default-value)**:** For providing fallback values