RunnablePassthrough and RunnableLambda in LangChain - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a RunnablePassthrough that returns the input as output.

LangChain

from langchain_core.runnables import RunnablePassthrough

passthrough = RunnablePassthrough()
result = passthrough.invoke([1])
print(result)

Drag options to blanks, or click blank then click option'

A'Hello World'

B123

CNone

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Passing None or a number instead of a string.

Expecting RunnablePassthrough to modify the input.

The RunnablePassthrough returns exactly what it receives. Passing a string like 'Hello World' will print the same string.

2fill in blank

medium

Complete the code to create a RunnableLambda that doubles the input number.

LangChain

from langchain_core.runnables import RunnableLambda

runnable = RunnableLambda(lambda x: x [1] 2)
result = runnable.invoke(5)
print(result)

Drag options to blanks, or click blank then click option'

A+

B-

C*

D//

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' adds instead of doubling.

Using '//' does integer division, not doubling.

The lambda multiplies the input by 2 to double it. Using '*' performs multiplication.

3fill in blank

hard

Fix the error in the RunnableLambda that should return the input string in uppercase.

LangChain

runnable = RunnableLambda(lambda x: x.[1]())
result = runnable.invoke('hello')
print(result)

Drag options to blanks, or click blank then click option'

Alower

Bupper

Ccapitalize

Dtitle

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'lower()' converts to lowercase, not uppercase.

Using 'capitalize()' only changes the first letter.

The 'upper()' method converts a string to uppercase. This fixes the error to produce 'HELLO'.

4fill in blank

hard

Fill both blanks to create a RunnableLambda that returns the length of the input string if it is longer than 3 characters.

LangChain

runnable = RunnableLambda(lambda x: len(x) if len(x) [1] 3 else [2])
print(runnable.invoke('test'))

Drag options to blanks, or click blank then click option'

A>

B0

CNone

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' reverses the condition.

Returning 0 instead of None changes the meaning.

The lambda checks if the input length is greater than 3 and returns its length; otherwise, it returns None.

5fill in blank

hard

Fill all three blanks to create a RunnableLambda that returns a dictionary with the input string as key and its uppercase as value if the string length is at least 4.

LangChain

runnable = RunnableLambda(lambda x: [1] if len(x) [2] 4 else [3])
print(runnable.invoke('code'))

Drag options to blanks, or click blank then click option'

A{x: x.upper()}

B>=

C{}

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '>=' excludes strings of length 4.

Returning None instead of an empty dictionary changes the output type.

The lambda returns a dictionary with the input and its uppercase if length is 4 or more; otherwise, it returns an empty dictionary.