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Thursday, June 16, 2016
Thursday, June 9, 2016
Codewars as a Training Tool
In this post I wanted to stick up for CodeWars and help explain to the novice coder why this site is so fucking awesome.
First, a little backstory. My boyfriend and I are both just starting out in this whole programming world. He was the one who told me about it first and when I first went to the site, I could barely get past the mandatory (but simple) coding challenges you have to get right in order to gain access to the full site.
Fast forward to today and I am on the site at least once a day training. It has become the best learning tool for me thus far. It challenges me every day, reminding me why I like coding. My boyfriend on the other, while he can build out an entire rails app, absolutely hates the site. I think it's because he hasn't given it enough of a chance (which is true), but he says his learning style is different (which also is true). Either way, I happen to think that anyone who uses the system the right way will soon too become a true believer. So, herein this post I present to you my methodology to using the site so that even you can conquer and earn your honor.
1. Select your level.
On the left hand side you will find everything you need to make sure you are doing problems within your range. The levels are from easiest, 8, to hardest, 1. Truth be told, it's best to have gone through the basics so that you can attempt the problems, but even if you are going along as you learn you can customize which problems to do (see below). Start off with 8, and move at your own pace. Some of the problems within are going to be a lot more difficult than some of the others. But give yourself some patience and work through them, absorbing everything you can.
2. Select what areas you want to train.
Once you've selected which level you want to compete in, you can then choose problems that have been tagged with certain areas of concentration. On the left hand side, under Tags, you can select Arrays, Numbers, Bugs, Fundamentals, etc. When I was starting out I found that the best thing that helped me was completing level 8 "bug" problems. They re-familiarized me with syntax and some other basic concepts that helped me to solve some other problems without the worry of that. If you're working through the problems while trying to master one area of a certain language, this will be one of the best ways to use CodeWars to do just that.
3. Don't be ashamed to forfeit honor.
No one likes to lose, obviously. But sometimes, you need to suck it up. There are problems that for some reason will not pass the tests, but once you click submit will actually work. Save for these cases, if you can't figure out why something won't work, it might be time to just unlock the solutions to that problem. It could be something simple you overlooked, but if it's something you can't figure out on your own, unlock the solutions and see how other people solved it. Think of it as learning, not cheating if you happen to be so honorable.
4. Read other peoples' answers.
Whether I submitted my answer or forfeited honor, I always look at other peoples' answers. There will be things in there that look like straight up gibberish. Even when I finished my Javascript book, there were things I had never seen before. Methods that would produce the right code with a fraction of the lines. It was insane. But it's also insanely insightful. Whenever there's something I don't understand I look it up, and you can get the general idea of the way something works once you see it.
Going through the site without any sort of order can be pretty depressing as a noob. You can easily get that "omg-I'm-never-going-to-understand-this-and-I-better-get-back-to-my-dead-end-job" feeling, but I swear with time, patience and a little order CodeWars can and will open all sorts of doors.
Wednesday, June 8, 2016
a/A Practice Problems: Nearby AZ
Practice Problem 8 of 21 and the first medium! It's exciting stuff happening 'round these parts. Without further adieu...
Check out past problems here:
Write a method that takes a string in and returns true if the letter "z" appears within three letters **after** an "a". You may assume that the string contains only lowercase letters.
This is a little trickier, but still employs the same methods and logic that we've already seen. A couple loops and if statements.
1. Declare our function with one parameter, string.
function nearbyAZ (string) {
}
}
2. I wanted to declare a variable, index1, that would hold the place of the position in which the letter "a" appears. This will be helpful later when determining if there's a "z" within the next three letters.
function nearbyAZ (string) {
var index1 = 0;
}
3. We want to loop through all the letters in order to see if there's an "a". The code block within the loop will be an if/else statement. If there's an "a", store it's index number in the variable, index1, and break out of the loop. Else, I want to increase index1 by one with each iteration of the loop. This way we will store the correct position number.
function nearbyAZ (string) {
var index1 = 0;
for (var i = 0; i < string.length; i++) {
if (string[i] === "a") {
index1 = i;
index1 = i;
break;
}
else {
index1++;
}
}
}
4. After the previous loop, I want another variable, index2, which will store the value of index1 + 1. This will be where our loop will start, and it should end at the third letter after the first a: index1 + 3.
function nearbyAZ (string) {
var index1 = 0;
for (var i = 0; i < string.length; i++) {
if (string[i] === "a") {
break;
}
else {
index1++;
}
}
var index2 = index1 + 1;
for (var j = index2; j <= index1 + 3; j++) {
}
}
5. Start the loop at index2 because we are only concerned with the first three letters after the letter "a". Likewise, we'll want to stop the loop once it reaches that third letter. An if statement is the last part required to return true or false if there's a "z".
function nearbyAZ (string) {
var index1 = 0;
for (var i = 0; i < string.length; i++) {
if (string[i] === "a") {
break;
}
else {
index1++;
}
}
var index2 = index1 + 1;
for (var j = index2; j <= index1 + 3; j++) {
if (string[j] === "z") {
return true;
}
}
return false;
}
Check out past problems here:
Tuesday, June 7, 2016
a/A Practice Problems: Palindrome
We have made it to the last of the "easy" problems. Rejoice! Here we go...
Write a method that takes a string and returns true if it is a palindrome. A palindrome is a string that is the same whether written backward or forward. Assume that there are no spaces; only lowercase letters will be given.
We know that we need a function that will take in a single parameter. We also want to declare an empty string that we can use to store the new word we will form by running a loop adding each letter from the string in reverse order. Lastly, we need a check to see if the original and the new string are the same, a palindrome, and return either true or false. Easy peasy.
1. Construct your function.
2. I declared a string that would hold the index position of the last letter of the string so as to use the variable in the loop instead. This isn't necessary. But you will want to declare a variable newString, which will be the original string in reversed order.
3. The loop starts with the index of the last letter, lastIndex, which we defined previously. It will continue so long as i is greater than or equal to 0, and will decrease by one each time. The code block inside the loop will concatenate each letter and form the new string in newString.
4. Lastly, an if statement that says if the original string and newString are the same will return true, else it will return false.
Next up the mediums! **tingles**
Check out past problems here:
Write a method that takes a string and returns true if it is a palindrome. A palindrome is a string that is the same whether written backward or forward. Assume that there are no spaces; only lowercase letters will be given.
We know that we need a function that will take in a single parameter. We also want to declare an empty string that we can use to store the new word we will form by running a loop adding each letter from the string in reverse order. Lastly, we need a check to see if the original and the new string are the same, a palindrome, and return either true or false. Easy peasy.
1. Construct your function.
function palindrome(string) {
}
}
2. I declared a string that would hold the index position of the last letter of the string so as to use the variable in the loop instead. This isn't necessary. But you will want to declare a variable newString, which will be the original string in reversed order.
function palindrome(string) {
var lastIndex = string.length - 1;
var newString = "";
}
var lastIndex = string.length - 1;
var newString = "";
}
3. The loop starts with the index of the last letter, lastIndex, which we defined previously. It will continue so long as i is greater than or equal to 0, and will decrease by one each time. The code block inside the loop will concatenate each letter and form the new string in newString.
function palindrome(string) {
var lastIndex = string.length - 1;
var newString = "";
for (var i = lastIndex; i >= 0; i--) {
newString += string[i];
}
}
var lastIndex = string.length - 1;
var newString = "";
for (var i = lastIndex; i >= 0; i--) {
newString += string[i];
}
}
4. Lastly, an if statement that says if the original string and newString are the same will return true, else it will return false.
function palindrome(string) {
var lastIndex = string.length - 1;
var newString = "";
for (var i = lastIndex; i >= 0; i--) {
newString += string[i];
}
if (string === newString) {
return true;
} else {
return false;
}
}
var lastIndex = string.length - 1;
var newString = "";
for (var i = lastIndex; i >= 0; i--) {
newString += string[i];
}
if (string === newString) {
return true;
} else {
return false;
}
}
Next up the mediums! **tingles**
Check out past problems here:
a/A Practice Problems: Count Vowels
Practice problem number 6 of 21. Here we go.
Problem: Write a method that takes a string and returns the number of vowels in the string. You may assume that all the letters are lower cased. You can treat "y" as a consonant.
This question was a nice and easy surprise after the time conversion mayhem. It's pretty straight forward, but let me explain how I thought to solve this one. I want to be have a function take in a string, and no matter how it is written, I would like it all to be in lowercase (there's a method for that). Secondly, I would like every letter to be separated so that I can write a loop to go through each individually to see if it is any of the vowels. If it is, I'll have a vowel counter and it will go up by one and I will be happy.
1. Declare your function with one parameter.
2. Let's convert myString to all lower case and split all the letters apart. You can put it all in one statement. We can also set it equal to the same variable and we don't need to declare it with var, since it's already implicitly declared in the parameter. We also need to declare another variable, vowelCount, and set it equal to 0. This is the variable that will increase if the loop finds any vowels.
3. Now we just need a loop to go through all the letters individually.
4. If we were to put vowelCount++ as the code block for our loop, it would could every letter and increase the total by the wrong amount. We only need vowels, so we need an if statement. I know there's a shorter way of doing this, but I don't know what that is so this will have to do.
The last thing to do is return the vowelCount at the end there. Make sure you remember to do this outside of the for loop, right before you end the function.
Until next time!
Check out past problems here:
Problem: Write a method that takes a string and returns the number of vowels in the string. You may assume that all the letters are lower cased. You can treat "y" as a consonant.
This question was a nice and easy surprise after the time conversion mayhem. It's pretty straight forward, but let me explain how I thought to solve this one. I want to be have a function take in a string, and no matter how it is written, I would like it all to be in lowercase (there's a method for that). Secondly, I would like every letter to be separated so that I can write a loop to go through each individually to see if it is any of the vowels. If it is, I'll have a vowel counter and it will go up by one and I will be happy.
1. Declare your function with one parameter.
function vowels(myString) {
}
}
2. Let's convert myString to all lower case and split all the letters apart. You can put it all in one statement. We can also set it equal to the same variable and we don't need to declare it with var, since it's already implicitly declared in the parameter. We also need to declare another variable, vowelCount, and set it equal to 0. This is the variable that will increase if the loop finds any vowels.
function vowels(myString) {
myString = myString.toLowerCase().split("");
var vowelCount = 0;
}
myString = myString.toLowerCase().split("");
var vowelCount = 0;
}
3. Now we just need a loop to go through all the letters individually.
function vowels(myString) {
myString = myString.toLowerCase().split("");
var vowelCount = 0;
for (var i = 0; i < myString.length; i++){
}
}
myString = myString.toLowerCase().split("");
var vowelCount = 0;
for (var i = 0; i < myString.length; i++){
}
}
4. If we were to put vowelCount++ as the code block for our loop, it would could every letter and increase the total by the wrong amount. We only need vowels, so we need an if statement. I know there's a shorter way of doing this, but I don't know what that is so this will have to do.
function vowels(myString) {
myString = myString.toLowerCase().split("");
var vowelCount = 0;
for (var i = 0; i < myString.length; i++){
if (myString[i] === "a" || myString[i] === "e" || myString[i] === "i" || myString[i] === "o" || myString[i] === "u" ||) {
vowelCount++;
}
}
return vowelCount;
}
myString = myString.toLowerCase().split("");
var vowelCount = 0;
for (var i = 0; i < myString.length; i++){
if (myString[i] === "a" || myString[i] === "e" || myString[i] === "i" || myString[i] === "o" || myString[i] === "u" ||) {
vowelCount++;
}
}
return vowelCount;
}
The last thing to do is return the vowelCount at the end there. Make sure you remember to do this outside of the for loop, right before you end the function.
Until next time!
Check out past problems here:
Monday, June 6, 2016
a/A Practice Problems: Time Conversion
Back at it again today! My plan is to continue solving these practice problems till I feel that "Oh hell yes!" sense of accomplishment. Let's get on with it.
Your mission: Write a method that will take in a number of minutes and returns a string that formats the number into "hours:minutes"
In keeping with tradition, think about how to solve this problem before doing any actual coding. I promise it's easier than Phoebe trying to teach Joey guitar cords without a guitar. #friends
The problem is asking us to convert any number of minutes given into the hours:minutes format. In order to do this there will have to be some math involved. Maybe set an hour counter equal to 0 and every time there's at least 60 that counter should go up by one. There should conversely be another counter that starts with the number passed in and decreases by 60 each time. Then it's just an issue of formatting, concatenating variables with strings and whatnot.
1. Let's go ahead and define our function with one argument. It is already provided in Ruby, but for Javascript it would be:
2. I defined two new variables here: hours, which I set equal to 0, and min, which I set equal to the parameter, minutes. (This last step might be repetitive, but it was how I solved the problem and it worked so I'm keeping it for now.)
3. Every time min is greater than or equal to 60, I want hours to increase by 1 and I want min to decrease by 60. To do this, I used a while loop. Inside the while loop, I want it to do all the math I explained above. Remember to include the counter (i -= 60) or you'll find yourself in an infinite loop. The same three parts of a for-loop are contained in a while loop, just the formatting is different.
4. Almost done! Just need to handle some special cases-- when there is less than ten minutes, you want it to read "06" or "0-whatever" not just "6". The second case you want it to handle is when there are 0 minutes, you want it to say "00". Sounds like an if statement.
This problem sent me for a loop. Yes, pun intended. It literally sent me into an infinite loop multiple times. Despite having to come back to this problem on different days to give it another shot, that little victory kinda made it all worth it. It's a pretty awesome feeling of accomplishment figuring these challenges out, even if it may not be the most concise code or employ best practices.. I have to actually know how do it first, amirite? Here's to the small victories!
P.S. I move to New York in TEN DAYS. (!!!!!!!!!!!!!)
Check out past problems here:
Your mission: Write a method that will take in a number of minutes and returns a string that formats the number into "hours:minutes"
In keeping with tradition, think about how to solve this problem before doing any actual coding. I promise it's easier than Phoebe trying to teach Joey guitar cords without a guitar. #friends
The problem is asking us to convert any number of minutes given into the hours:minutes format. In order to do this there will have to be some math involved. Maybe set an hour counter equal to 0 and every time there's at least 60 that counter should go up by one. There should conversely be another counter that starts with the number passed in and decreases by 60 each time. Then it's just an issue of formatting, concatenating variables with strings and whatnot.
1. Let's go ahead and define our function with one argument. It is already provided in Ruby, but for Javascript it would be:
function time_conversion(minutes) {
}
}
2. I defined two new variables here: hours, which I set equal to 0, and min, which I set equal to the parameter, minutes. (This last step might be repetitive, but it was how I solved the problem and it worked so I'm keeping it for now.)
function time_conversion(minutes) {
var hours = 0;
var min = minutes;
}
var hours = 0;
var min = minutes;
}
3. Every time min is greater than or equal to 60, I want hours to increase by 1 and I want min to decrease by 60. To do this, I used a while loop. Inside the while loop, I want it to do all the math I explained above. Remember to include the counter (i -= 60) or you'll find yourself in an infinite loop. The same three parts of a for-loop are contained in a while loop, just the formatting is different.
function time_conversion(minutes) {
var hours = 0;
var min = minutes;
var i = min;
while (i >= 60)
hours++;
min -= 60;
i -= 60;
}
}
var hours = 0;
var min = minutes;
var i = min;
while (i >= 60)
hours++;
min -= 60;
i -= 60;
}
}
4. Almost done! Just need to handle some special cases-- when there is less than ten minutes, you want it to read "06" or "0-whatever" not just "6". The second case you want it to handle is when there are 0 minutes, you want it to say "00". Sounds like an if statement.
function time_conversion(minutes) {
var hours = 0;
var min = minutes;
var i = min;
while (i >= 60)
hours++;
min -= 60;
i -= 60;
}
if (min === 0) {
min = "00"
return hours + ":" + min;
}
else if (min < 10) {
min = "0" + min;
return hours + ":" + min;
}
else {
return hours + ":" + min;
}
}
var hours = 0;
var min = minutes;
var i = min;
while (i >= 60)
hours++;
min -= 60;
i -= 60;
}
if (min === 0) {
min = "00"
return hours + ":" + min;
}
else if (min < 10) {
min = "0" + min;
return hours + ":" + min;
}
else {
return hours + ":" + min;
}
}
This problem sent me for a loop. Yes, pun intended. It literally sent me into an infinite loop multiple times. Despite having to come back to this problem on different days to give it another shot, that little victory kinda made it all worth it. It's a pretty awesome feeling of accomplishment figuring these challenges out, even if it may not be the most concise code or employ best practices.. I have to actually know how do it first, amirite? Here's to the small victories!
P.S. I move to New York in TEN DAYS. (!!!!!!!!!!!!!)
Check out past problems here:
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