Ever wondered how much power Ruby's count method has? Besides counting the elements of an array, it can do pretty awesome things. So let's start with the most common use case: counting the elements of an array.
irb> numbers = [1,2,5,3,6,2,5,3]
=> [1, 2, 5, 3, 6, 2, 5, 3]
irb> numbers.count
=> 8
Converts a comma-separated values (CSV) string to a 2D array of objects. The first row of the string is used as the title row.
const CSVToJSON = (data, delimiter = ',') => {
const titles = data.slice(0, data.indexOf('\n')).split(delimiter);
return data
.slice(data.indexOf('\n') + 1)
.split('\n')
.map(v => {
Computes the new ratings between two or more opponents using the Elo rating system. It takes an array of pre-ratings and returns an array containing post-ratings. The array should be ordered from best performer to worst performer (winner -> loser).
Use the exponent ** operator and math operators to compute the expected score (chance of winning). of each opponent and compute the new rating for each. Loop through the ratings, using each permutation to compute the post-Elo rating for each player in a pairwise fashion. Omit the second argument to use the default kFactor of 32.
const elo = ([...ratings], kFactor = 32, selfRating) => {
const [a, b] = ratings;
const expectedScore = (self, opponent) => 1 / (1 + 10 ** ((opponent - self) / 400));
const newRating = (rating, i) =>
(selfRating || rating) + kFactor * (i - expectedScore(i ? a : b, i ? b : a));
if (ratings.length === 2) return [newRating(a, 1), newRating(b, 0)];
| const intersectionBy = (a, b, fn) => { | |
| const s = new Set(b.map(fn)); | |
| return a.filter(x => s.has(fn(x))); | |
| }; | |
| intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [2.1] |
| dataset$Age = ifelse(is.na(dataset$Age), | |
| ave(dataset$Age, FUN = function(x) mean(x, na.rm =TRUE)), | |
| dataset$Age) | |
| dataset$Salary = ifelse(is.na(dataset$Salary), | |
| ave(dataset$Salary, FUN = function(x) mean(x, na.rm =TRUE)), | |
| dataset$Salary) |
| from sklearn.preprocessing import LabelEncoder, OneHotEncoder | |
| labelencoder_X = LabelEncoder() | |
| X[:, 0] = labelencoder_X.fit_transform(X[:, 0]) | |
| onehotencoder = OneHotEncoder(categorical_features = [0]) | |
| X = onehotencoder.fit_transform(X).toarray() | |
| # Encoding the Dependent Variable | |
| labelencoder_y = LabelEncoder() | |
| y = labelencoder_y.fit_transform(y) |
| # Encoding categorical data | |
| dataset$Country = factor(dataset$Country, | |
| levels = c('France', 'Spain', 'Germany'), | |
| labels = c(1, 2, 3)) | |
| dataset$Purchased = factor(dataset$Purchased, | |
| levels = c('No', 'Yes'), | |
| labels = c(0, 1)) |
| // source: person.proto | |
| /** | |
| * @fileoverview | |
| * @enhanceable | |
| * @suppress {messageConventions} JS Compiler reports an error if a variable or | |
| * field starts with 'MSG_' and isn't a translatable message. | |
| * @public | |
| */ | |
| // GENERATED CODE -- DO NOT EDIT! |
| ERROR: Error installing mysql2: | |
| ERROR: Failed to build gem native extension. | |
| current directory: /Users/amkurian/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/mysql2-0.5.2/ext/mysql2 | |
| /Users/amkurian/.rbenv/versions/2.5.1/bin/ruby -r ./siteconf20200715-2791-2g860l.rb extconf.rb --with-mysql-config=/usr/local/mysql/bin/mysql_config | |
| checking for rb_absint_size()... yes | |
| checking for rb_absint_singlebit_p()... yes | |
| checking for rb_wait_for_single_fd()... yes | |
| ----- | |
| Cannot find mysql_config at /usr/local/mysql/bin/mysql_config |