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August, 2020

Intro 🌐

Problem solving is an important skill, for your career and your life in general.

That’s why I take interesting katas of all levels, customize them and explain how to solve them.

Understanding the Exercise❗

First, we need to understand the exercise! If you don’t understand it, you can’t solve it!.

My personal method:

1. Input: What do I put in?
2. Output: What do I want to get out?

Today’s exercise

Source: Codewars

Today as small kata with a little bit of historical background about Sigmund Freud.

Write a function `toFreud`, that accepts one parameter: `myString`.

Given a string, e.g. `"Sigmund Freud"`, return the string with every word replaced by the word `"sex"`, e.g. `"sex sex"`. An empty string or no argument should result in an empty string.

Input: a string.

Output: a string.

I think I understand the exercise (= what I put into the function and what I want to get out of it).

Now, I need the specific steps to get from input to output.

I try to do this in small baby steps:

1. Return an empty string if string is empty or no argument
2. Loop over every word of the string
3. Replace each word with `"sex"`
4. Return a string of all new words

Example:

• Input: `"Sigmund Freud"`
• Return an empty string if string is empty or no argument: `false`
• Iteration 1: “Sigmund” => replace it => `"sex"`
• Iteration 2: “Freud” => replace it => `"sex"`
• Return a string of all new words: `"sex sex"`
• Output: `"sex sex"`

Implementation (functional) ⛑

``````function toFreud(myString) {
return !myString
? "" // return an empty string if string is empty or no argument
: myString
.split(" ") // split string into words
.map((word) => "sex") // replace each word with `"sex"`
.join(" "); // put replaced words together
}``````

Result

``````console.log(toFreud("Sigmund Freud"));
// "sex sex" ✅

console.log(toFreud(""));
// ""  ✅``````

Implementation (regex) ⛑

``````function toFreudRegex(myString) {
return !myString
? ""
: myString.replace(/\S+/g, "sex"); // find all places that have "one or more non-white space", replace them with "sex"
}``````

The regex `\S` character class “matches a single character other than white space”. You can read about it here.

The regex `+` quantifier “matches the preceding item 1 or more times”. You can read about it here.

Result

``````console.log(toFreud("Sigmund Freud"));
// "sex sex" ✅

console.log(toFreud(""));
// ""  ✅``````

Playground ⚽

You can play around with the code here

Next Part ➡️

Great work!

We learned how to use `split`, `map`, `join`, `replace` and some regex.

I hope you can use your new learnings to solve problems more easily!

Next time, we’ll solve another interesting kata. Stay tuned!

If I should solve a specific kata, shoot me a message here.

If you want to read my latest stuff, get in touch with me!