Write a function sentencesByLength that reads the text in the file filename and returns a dictionary where each key represents a number of words, and the corresponding value is a list of those sentences in the file that have that number of words.For example the file sentences1.txt has two sentences with 9 words, so the returned dictionary will contain an entry with the key 9 and the two sentences of length 9 contained in a list: { 9:[‘The quick brown fox jumps over the lazy dog.’, “There’s a message for you if you look up.”], …}. The quick brown fox jumps over the lazy dog. There’s a message for you if you look up. Just go ahead and press that button
Firstly, welcome to the forums.
While we are primarily here to help people with their Free Code Camp progress, we are open to people on other paths, too. Some of what you are asking is pretty trivial in the Free Code Camp context, so you might find that if you’re not getting the instruction and material you need in your current studies, the FCC curriculum will really help you get started. At a modest guess I’d say investing a 4-5 hours working through the curriculum here will really pay off. You can find the curriculum at https://www.freecodecamp.org/learn.
With your current questions, we don’t have enough context to know what you already know or don’t know, so it is impossible to guide you without just telling you the answer (which we won’t do).
It is pretty typical on here for people to share a codepen / repl.it / jsfiddle example of what they have tried so that anyone helping has more of an idea of what help is actually helpful.
Please provide some example of what you’ve tried and I’m sure you’ll get more help.
Happy coding 
When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.
You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.
See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (’).