PromptTemplate basics in LangChain - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a PromptTemplate in Langchain?

A PromptTemplate is a way to create text prompts with placeholders that you can fill with different values. It helps you build dynamic prompts easily.

beginner

How do you define placeholders in a PromptTemplate?

Placeholders are defined using curly braces like {placeholder_name} inside the template string. These get replaced with actual values when you run the prompt.

beginner

What method do you use to fill a PromptTemplate with values?

You use the format() method and pass keyword arguments with keys matching the placeholder names to fill the template.

beginner

Why use PromptTemplate instead of plain strings?

PromptTemplate helps keep your prompts organized and reusable. It avoids mistakes by clearly marking where values go and makes it easy to change parts without rewriting the whole prompt.

beginner

Show a simple example of creating and using a PromptTemplate.

Example:<br>template = "Hello, {name}!"<br>prompt = PromptTemplate(template=template)<br>filled = prompt.format(name="Alice")<br>Output: "Hello, Alice!"

What symbol is used to mark placeholders in a PromptTemplate?

A []

B ()

C <>

D {}

Placeholders in PromptTemplate are marked with curly braces {}.

Which method fills a PromptTemplate with actual values?

A fill()

B format()

C replace()

D insert()

The format() method is used to replace placeholders with real values.

Why is using PromptTemplate helpful?

A It makes prompts static and unchangeable

B It automatically runs the prompt on a server

C It helps organize and reuse prompts with dynamic parts

D It converts prompts into images

PromptTemplate helps keep prompts organized and reusable with dynamic placeholders.

If your template is "Hi, {user}!", how do you fill it with user='Bob'?

A prompt.format(user='Bob')

B prompt.fill('Bob')

C prompt.insert(user='Bob')

D prompt.replace('user', 'Bob')

You use format() with the placeholder name as keyword argument.

What happens if you forget to provide a value for a placeholder?

A An error occurs when formatting

B The prompt runs with default values

C The placeholder is removed silently

D The placeholder stays as is in the output

Missing values for placeholders cause an error during format() call.

Explain what a PromptTemplate is and why it is useful in Langchain.

Think about how you would write a letter with blanks to fill in later.

Describe the steps to create and use a PromptTemplate with an example.

Imagine filling out a form with your name and details.