w1d4

Question 1

How do you start a fresh project with bundle? What does this do?

Answer 1

bundle init

it creates an empty Gemfile with instructions on how to add gems

Question 2

What’s the command to create an empty Gemfile with instructions on how to add gems?

Answer 2

bundle init

Question 3

How do we install the gems for our project?

Answer 3

bundle install

Question 4

What does bundle install do?

Answer 4

installs the gems for our project that we’ve specified in our Gemfile

Question 5

Can we pass a has to a method without curly braces?

Answer 5

Yes, only if it’s the final argument passed in.

Question 6

How can we set up an attr_reader that can only be accessed internally?

Answer 6

private

attr_reader :whatever

Question 7

What’s a recursive solution for creating a range(start,finish) exclusive method?

ex: range(1,5) => [1,2,3,4]

Answer 7

base case: if start == finish, return [ ]

A: chop off the leftmost number and add to an empty array

B: call range like so: range(start+1,finish)

return A + B

Question 8

What’s a recursive solution for generating the first n fib numbers?

Answer 8

base cases:
return [ ] if n == 0
return [0] if n == 1
return [0,1] if n == 2

general case:
fibs(n-1).push fibs(n-1)[-2] + fibs(n-1)[-1]

optimize: make one call to fibs

Question 9

What are the two main reasons to use git?

Answer 9

We can keep track of changes and know who changed what.

Easy to work on a team. Multiple people can work on a project at once.

Question 10

How do you see the state of your staging area with git?

Answer 10

git status

Question 11

What does git status do?

Answer 11

Displays the state of your staging area.

Question 12

How do you see the differences you’ve made in your staging area?

Answer 12

git diff –staged

Question 13

How do you make a snapshot of your current staging area with git?

Answer 13

git commit -m “this is the commit message”

Question 14

How do you see all the branches your team is working on?

Answer 14

git branch

Question 15

What does git branch do?

Answer 15

Shows all the branches your team is working on

Question 16

How do you add all the files in a directory to git?

Answer 16

git add -A

Question 17

What does this do:

git add -A

Answer 17

Adds all the files in the current directory into git

Question 18

How do you see a history of commits/merges/etc made in git?

Answer 18

git log

Question 19

What does git log do?

Answer 19

Shows a history of commits/merges/etc made in git

Question 20

How do you switch to a particular branch in git?

Answer 20

git co [branchname]

Question 21

What does this do:

git co [branchname]

Answer 21

Switches to a different branch

Question 22

How do we merge changes from one branch into another?

Answer 22

make changes on a new branch
git co [branch to merge into]
git merge [branch to merge from]

Question 23

Let’s say we have a public repo on github.

How do we push the master branch of our repo up to that github repo for the first time?

Answer 23

git remote add origin something@github.com:[username]/[reponame].git

git push -u origin master

Question 24

How do you revert to a previous version?

Answer 24

first do: git log

second: take the hash from the commit you want to revert to.
third: git co [hash]

Question 25

How do you revert all changes to all files since the last commit?

Answer 25

git reset --hard | dangerous!

Question 26

What 5 actions in git do we need to memorize?

Answer 26

``` adding committing merging pushing branching ```

Question 27

What are the three states a file can exist as within git?

Answer 27

modified staged committed

Question 28

How do you set up a new repo and connect it to github?

Answer 28

git init | git remote add your_alias https://github.com/username/reponame

Question 29

What's a good name for a git remote alias?

Answer 29

origin

Question 30

How do you add a file to git?

Answer 30

git add [file(s)]

Question 31

What does this do: git add [file(s)]

Answer 31

Adds some files to the staging area.

Question 32

How do you send changes to a remote repo (on a regular basis)?

Answer 32

git push

Question 33

Why would you stay away from a gem with fewer than 100-500 followers?

Answer 33

Less people actively working to fix bugs.

Question 34

What is an atomic operation?

Answer 34

An operation whose changes are rolled back if they are somehow interrupted before completion. This helps prevent corruption.

Question 35

What type of operation does this describe: It's changes are rolled back if they are somehow interrupted before completion.

Answer 35

atomic operation

Question 36

What does semantic versioning refer to?

Answer 36

x. y.z versioning | i. e. OSX 10.11.1

Question 37

What is the foremost principle in Agile?

Answer 37

rapid, iterative design

Question 38

What are 3 alternative development paradigms to Agile?

Answer 38

waterfall prototype spiral

Question 39

HTML What are the two main Form methods?

Answer 39

GET | POST

Question 40

HTML What are some Input type values? ``` 7+: 5 stars 5-6: 4 stars 4: 3 stars 3: 2 stars 2: 1 star ```

Answer 40

``` button checkbox color date email hidden number password radio search url ```

Question 41

How do you set up multiple radio inputs to create a multiple-choice?

Answer 41

Give each radio input element the same attribute value

Question 42

How do you set your username/email for git?

Answer 42

git config [--global] user.email ( --global is optional. when not used, only the config for the current repo will be set ).

Question 43

What's the syntax for a shell alias?

Answer 43

alias [shorthand]='[command]'

Question 44

How do you add files to the staging area?

Answer 44

git add [files]

Question 45

How do you roll back to a particular commit?

Answer 45

git reset commit_SHA commit_SHA only needs the first 7 chars of a SHA

Question 46

What are 3 ways to backtrack in git?

Answer 46

git checkout HEAD filename git reset HEAD filename git reset commit_SHA

Question 47

How do you insert an element into an existing array?

Answer 47

Array#insert(index, object)

Question 48

What will this do: Array#insert(index, object)

Answer 48

Insert an element into an existing array

Question 49

High-level: how do you recursively generate subsets?

Answer 49

base case: empty array => [ [ ] ] pull the element off the end recursively generate subsets for the remaining elements and store to smaller_subset create a new bigger_subset array and fill it by adding the element we pulled off the end to the end of each subset in smaller_subset return smaller_subset + bigger_subset

Question 50

How do you remove a single file from the staging area?

Answer 50

git reset HEAD -- filename