1  ---
 2  title: "StringJoiner"
 3  id: stringjoiner
 4  slug: "/stringjoiner"
 5  description: "Component to join strings from different components into a list of strings."
 6  ---
 7  
 8  # StringJoiner
 9  
10  Component to join strings from different components into a list of strings.
11  
12  |                                        |                                                                                                 |
13  | :------------------------------------- | :---------------------------------------------------------------------------------------------- |
14  | **Most common position in a pipeline** | After at least two other components to join their strings                                       |
15  | **Mandatory run variables**            | “strings”: Multiple strings from connected components.                                          |
16  | **Output variables**                   | “strings”: A list of merged strings                                                             |
17  | **API reference**                      | [Joiners](/reference/joiners-api)                                                                      |
18  | **GitHub link**                        | https://github.com/deepset-ai/haystack/blob/main/haystack/components/joiners/string_joiner.py |
19  
20  ## Overview
21  
22  The `StringJoiner` component collects multiple string outputs from various pipeline components and combines them into a single list. This is useful when you need to merge several strings from different parts of a pipeline into a unified output.
23  
24  ## Usage
25  
26  ```python
27  from haystack.components.joiners import StringJoiner
28  from haystack.components.builders import PromptBuilder
29  from haystack.core.pipeline import Pipeline
30  
31  string_1 = "What's Natural Language Processing?"
32  string_2 = "What is life?"
33  
34  pipeline = Pipeline()
35  pipeline.add_component("prompt_builder_1", PromptBuilder("Builder 1: {{query}}"))
36  pipeline.add_component("prompt_builder_2", PromptBuilder("Builder 2: {{query}}"))
37  pipeline.add_component("string_joiner", StringJoiner())
38  
39  pipeline.connect("prompt_builder_1.prompt", "string_joiner.strings")
40  pipeline.connect("prompt_builder_2.prompt", "string_joiner.strings")
41  
42  result = pipeline.run(
43      data={
44          "prompt_builder_1": {"query": string_1},
45          "prompt_builder_2": {"query": string_2},
46      },
47  )
48  
49  print(result)
50  ```