powercore

PowerCore extends the Ruby Core with useful extensions.

76
1
Ruby

PowerCore

Code Climate
Build Status

PowerCore extends the Ruby Core with useful extensions.

There are Ruby gems that do something similar, such as
ActiveSuppor Core Extensions or Powerpack.

In this case, this is just a collection of extensions for reference, not a
Ruby gem. Who wants a new dependency in the code base? Just borrow the code
that you consider useful, but be careful; most of the time I have created new
methods but sometimes I have overridden the default Ruby implementation, or even
worse, I have removed Ruby methods to do some tricks. Come and see!

Array

average

Calculates the mean of the elements.

[1, 2, 3, 4].average  # => 2.5

Negative index drop

Drops n elements from end of the array.

[1, 2, 3, 4].drop(-2)  # => [1, 2]

If you pass a positive number, it delegates to the original implementation.

[1, 2, 3, 4].drop(2)  # => [3, 4]

except

Returns the array without the indexes specified.

[1, 2, 3, 4].except(1, 2)  # => [1, 4]

fetch_dig

Extracts the nested value specified by the sequence of indexes.

[[1, [2, 3]]].fetch_dig(0, 1, 1)  # => 3

If the key can’t be found with no other arguments, it will raise an IndexError exception.

[[1, [2, 3]]].fetch_dig(1, 2, 3)  # => IndexError

If the key can’t be found and an optional code block is specified, then that will be run and its result returned.

[[1, [2, 3]]].fetch_dig(1, 2, 3) { 2 }  # => 2

head

Returns the head of the array.

[1, 2, 3].head  # => 1

histogram

Builds the histogram in a hash.

[2, 1, 2, 2, 3, 3].histogram  # => {1=>1, 2=>3, 3=>2}

init

The initial part of the array without its last element.

[1, 2, 3].init  # => [1, 2]

mean

Calculates the mean of the elements.

[1, 2, 3, 4].mean  # => 2.5

median

Calculates the median of the elements.

[1, 2, 3, 4, 5].median  # => 3
[1, 2, 3, 4].median     # => 2.5

mode

Finds the mode value/s.

[1, 2, 3, 4].mode     # => [1, 2, 3, 4]
[1, 2, 2, 4].mode     # => [2]
[1, 1, 2, 4, 4].mode  # => [1, 4]

percentile

Returns the percentile value for a given percentage.

[1, 2, 3, 4].percentile(49)     # => 2
[1, 2, 3, 4].percentile(50)     # => 3
[1, 2, 3, 4, 5].percentile(50)  # => 3

Negative index take

Returns n elements from end of the array.

[1, 2, 3, 4].take(-2)  # => [3, 4]

If you pass a positive number, it delegates to the original implementation.

[1, 2, 3, 4].take(2)  # => [1, 2]

tail

Returns the tail of the array.

[1, 2, 3, 4].tail  # => [2, 3, 4]

transpose array of ranges

Assumes that self is an array of ranges and transposes the rows and columns.

[(1..2), (3..4)].transpose  # => [[1, 3], [2, 4]]

It also works with the original implementation, assuming an array of arrays.

[[1, 2], [3, 4]].transpose  # => [[1, 3], [2, 4]]

Date

now

Returns the current day.

Date.now  # => #<Date: 2016-03-29 ((2457477j,0s,0n),+0s,2299161j)>

Integer

clamp

Clamps a comparable between a lower and upper bound.

1.clamp(3, 6)  # => 3
5.clamp(3, 6)  # => 5
8.clamp(3, 6)  # => 6

1.clamp(3..6)  # => 3
5.clamp(3..6)  # => 5
8.clamp(3..6)  # => 6

degrees

Converts a number of degrees into radians.

90.degrees  # => 1.5707963267948966

negative

Negates the number.

1.negative  # => -1

ordinal

Returns the ordinal of the number.

1.ordinal  # => "1st"
2.ordinal  # => "2nd"

Hash

except

Returns the hash without the keys specified.

{ a: 1, b: nil, c: nil, d: 4 }.except(:b, :d)  # => {a: 1, c: nil}

fetch_dig

Extracts the nested value specified by the sequence of keys.

{ foo: { bar: { baz: 1 } }}.fetch_dig(:foo, :bar, :baz)  # => 1

If the key can’t be found with no other arguments, it will raise an KeyError exception.

{ foo: { bar: { baz: 1 } } }.fetch_dig(:foo, :zot, :xyz)  # => KeyError

If the key can’t be found and an optional code block is specified, then that will be run and its result returned.

{ foo: { bar: { baz: 1 } } }.fetch_dig(:foo, :zot, :xyz) { 2 }  # => 2

first

Returns the first elements of the hash.

{ a: 1, b: 2, c: 3 }.first     # => { a: 1 }
{ a: 1, b: 2, c: 3 }.first(2)  # => { a: 1, b: 2 }

head

Returns the first element of the hash.

{ a: 1, b: 2, c: 3 }.head  # => { a: 1 }

init

The initial part of the hash without its last element.

{ a: 1, b: 2, c: 3 }.init  # => { a: 1, b: 2 }

last

The initial part of the hash without its last element.

{ a: 1, b: 2, c: 3 }.last  # => { c: 3 }

tail

The rest of the hash without its first element

{ a: 1, b: 2, c: 3 }.tail  # => { b: 2, c: 3 }

Kernel

λ

λ is lambda.

my_proc = λ { }

Object

assert

Asserts an expression.

assert(1 == 2)  # => AssertError: AssertError
assert(1 == 1)  # => nil

in?

Returns true if self is present in the given object.

1.in?([1, 2, 3])            # => true
"lo".in?("hello")           # => true
:b.in?({ a: 100, b: 200 })  # => true

metaclass

Returns the eigenclass.

Object.new.metaclass  # => #<Class:#<Object:0x007fc6427d1058>>

not_in?

Returns true if self is not present in the given object.

4.not_in?([1, 2, 3])            # => true
"mo".not_in?("hello")           # => true
:c.not_in?({ a: 100, b: 200 })  # => true

not_nil?

Returns true when an object is not nil.

nil.not_nil?  # => false
1.not_nil?    # => true

Pipe operator

Pipe operator à la Bash/Elixir.

[1, 2, 3] |
  ->(array)  { array.first } |
  ->(int)    { int.to_s } |
  ->(string) { string + "2" }
# => "12"

[1, 2, 3] | :first | :to_s | ->(s) { s + "2" }  # => "12"

Range

head

Returns the first object in the range.

(0..3).head      # => 0
("a".."z").head  # => "a"

init

The initial part of the range without its last element.

(0..3).init      # => 0..2
("a".."z").init  # => "a".."y"

tail

The rest of the range without its first element.

(0..3).tail      # => 1..3
("a".."z").tail  # => "b".."z"

String

first

Returns the first characters of the string.

"abc".first     # => "a"
"abc".first(2)  # => "ab"

head

Returns the first characters of the string.

"abc".head  # => "a"

init

The initial part of the string without its last element.

"abc".init  # => "ab"

last

Returns the last characters of the string.

"abc".last     # => "c"
"abc".last(2)  # => "bc"

tail

The rest of the string without its first element.

"abc".tail  # => "bc"

to_bool

Converts a string to boolean.

"true".to_bool   # => true
"false".to_bool  # => false

Who made this?

This was made by Arturo Herrero under the MIT License. Find me on Twitter
@ArturoHerrero.