langchain/docs/modules/prompts/example_selectors/examples/ngram_overlap.ipynb

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    "# NGram Overlap ExampleSelector\n",
    "\n",
    "The NGramOverlapExampleSelector selects and orders examples based on which examples are most similar to the input, according to an ngram overlap score. The ngram overlap score is a float between 0.0 and 1.0, inclusive. \n",
    "\n",
    "The selector allows for a threshold score to be set. Examples with an ngram overlap score less than or equal to the threshold are excluded. The threshold is set to -1.0, by default, so will not exclude any examples, only reorder them. Setting the threshold to 0.0 will exclude examples that have no ngram overlaps with the input.\n"
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    "from langchain.prompts import PromptTemplate\n",
    "from langchain.prompts.example_selector.ngram_overlap import NGramOverlapExampleSelector\n",
    "from langchain.prompts import FewShotPromptTemplate, PromptTemplate\n",
    "\n",
    "example_prompt = PromptTemplate(\n",
    "    input_variables=[\"input\", \"output\"],\n",
    "    template=\"Input: {input}\\nOutput: {output}\",\n",
    ")\n",
    "\n",
    "# These are a lot of examples of a pretend task of creating antonyms.\n",
    "examples = [\n",
    "    {\"input\": \"happy\", \"output\": \"sad\"},\n",
    "    {\"input\": \"tall\", \"output\": \"short\"},\n",
    "    {\"input\": \"energetic\", \"output\": \"lethargic\"},\n",
    "    {\"input\": \"sunny\", \"output\": \"gloomy\"},\n",
    "    {\"input\": \"windy\", \"output\": \"calm\"},\n",
    "]"
   ]
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   "cell_type": "code",
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    "# These are examples of a fictional translation task.\n",
    "examples = [\n",
    "    {\"input\": \"See Spot run.\", \"output\": \"Ver correr a Spot.\"},\n",
    "    {\"input\": \"My dog barks.\", \"output\": \"Mi perro ladra.\"},\n",
    "    {\"input\": \"Spot can run.\", \"output\": \"Spot puede correr.\"},\n",
    "]"
   ]
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    "example_prompt = PromptTemplate(\n",
    "    input_variables=[\"input\", \"output\"],\n",
    "    template=\"Input: {input}\\nOutput: {output}\",\n",
    ")\n",
    "example_selector = NGramOverlapExampleSelector(\n",
    "    # These are the examples it has available to choose from.\n",
    "    examples=examples, \n",
    "    # This is the PromptTemplate being used to format the examples.\n",
    "    example_prompt=example_prompt, \n",
    "    # This is the threshold, at which selector stops.\n",
    "    # It is set to -1.0 by default.\n",
    "    threshold=-1.0,\n",
    "    # For negative threshold:\n",
    "    # Selector sorts examples by ngram overlap score, and excludes none.\n",
    "    # For threshold greater than 1.0:\n",
    "    # Selector excludes all examples, and returns an empty list.\n",
    "    # For threshold equal to 0.0:\n",
    "    # Selector sorts examples by ngram overlap score,\n",
    "    # and excludes those with no ngram overlap with input.\n",
    ")\n",
    "dynamic_prompt = FewShotPromptTemplate(\n",
    "    # We provide an ExampleSelector instead of examples.\n",
    "    example_selector=example_selector,\n",
    "    example_prompt=example_prompt,\n",
    "    prefix=\"Give the Spanish translation of every input\",\n",
    "    suffix=\"Input: {sentence}\\nOutput:\", \n",
    "    input_variables=[\"sentence\"],\n",
    ")"
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      "Give the Spanish translation of every input\n",
      "\n",
      "Input: Spot can run.\n",
      "Output: Spot puede correr.\n",
      "\n",
      "Input: See Spot run.\n",
      "Output: Ver correr a Spot.\n",
      "\n",
      "Input: My dog barks.\n",
      "Output: Mi perro ladra.\n",
      "\n",
      "Input: Spot can run fast.\n",
      "Output:\n"
     ]
    }
   ],
   "source": [
    "# An example input with large ngram overlap with \"Spot can run.\"\n",
    "# and no overlap with \"My dog barks.\"\n",
    "print(dynamic_prompt.format(sentence=\"Spot can run fast.\"))"
   ]
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     "text": [
      "Give the Spanish translation of every input\n",
      "\n",
      "Input: Spot can run.\n",
      "Output: Spot puede correr.\n",
      "\n",
      "Input: See Spot run.\n",
      "Output: Ver correr a Spot.\n",
      "\n",
      "Input: Spot plays fetch.\n",
      "Output: Spot juega a buscar.\n",
      "\n",
      "Input: My dog barks.\n",
      "Output: Mi perro ladra.\n",
      "\n",
      "Input: Spot can run fast.\n",
      "Output:\n"
     ]
    }
   ],
   "source": [
    "# You can add examples to NGramOverlapExampleSelector as well.\n",
    "new_example = {\"input\": \"Spot plays fetch.\", \"output\": \"Spot juega a buscar.\"}\n",
    "\n",
    "example_selector.add_example(new_example)\n",
    "print(dynamic_prompt.format(sentence=\"Spot can run fast.\"))"
   ]
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     "text": [
      "Give the Spanish translation of every input\n",
      "\n",
      "Input: Spot can run.\n",
      "Output: Spot puede correr.\n",
      "\n",
      "Input: See Spot run.\n",
      "Output: Ver correr a Spot.\n",
      "\n",
      "Input: Spot plays fetch.\n",
      "Output: Spot juega a buscar.\n",
      "\n",
      "Input: Spot can run fast.\n",
      "Output:\n"
     ]
    }
   ],
   "source": [
    "# You can set a threshold at which examples are excluded.\n",
    "# For example, setting threshold equal to 0.0\n",
    "# excludes examples with no ngram overlaps with input.\n",
    "# Since \"My dog barks.\" has no ngram overlaps with \"Spot can run fast.\"\n",
    "# it is excluded.\n",
    "example_selector.threshold=0.0\n",
    "print(dynamic_prompt.format(sentence=\"Spot can run fast.\"))"
   ]
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   "cell_type": "code",
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     "text": [
      "Give the Spanish translation of every input\n",
      "\n",
      "Input: Spot can run.\n",
      "Output: Spot puede correr.\n",
      "\n",
      "Input: Spot plays fetch.\n",
      "Output: Spot juega a buscar.\n",
      "\n",
      "Input: Spot can play fetch.\n",
      "Output:\n"
     ]
    }
   ],
   "source": [
    "# Setting small nonzero threshold\n",
    "example_selector.threshold=0.09\n",
    "print(dynamic_prompt.format(sentence=\"Spot can play fetch.\"))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "09633aa8",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
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     "text": [
      "Give the Spanish translation of every input\n",
      "\n",
      "Input: Spot can play fetch.\n",
      "Output:\n"
     ]
    }
   ],
   "source": [
    "# Setting threshold greater than 1.0\n",
    "example_selector.threshold=1.0+1e-9\n",
    "print(dynamic_prompt.format(sentence=\"Spot can play fetch.\"))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "39f30097",
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