Useful javascript
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This document discusses various Ruby array and string methods like capitalize, each_char, map, sample, shuffle, zip, and more. Code snippets demonstrate how to use these methods on arrays and strings in Ruby. The document also discusses using Node.js and IRB to test Ruby code snippets and the potential to write tests for Ruby code using a BDD style.
![Array.each
[1,2,3].each {|i| print i+5 } #=> 6 7 8
[1,2,3].each(function(i){ print( i+5) }) > 6 7 8
[1,2,3].reverse_each(function(i){ print( i+5) }) >
8 7 6
[{a:1,b:2},{a:2,b:3},{a:3,b:4}].each(function(item){
print(item.a+item.b)
}) > 3 5 7](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-12-320.jpg)
![Array.map
a = [ "a", "b", "c", "d" ]
a.map {|x|x+"!" } #=> ["a!", "b!", "c!", "d!"]
a #=> ["a", "b", "c", "d"]
var a = [ "a", "b", "c", "d" ];
a.map(function(i,item){return x+”!”}) > ["a!",
"b!", "c!", "d!"]
a > [ "a",
"b", "c", "d" ]](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-13-320.jpg)
![Array.remove_if
(Array.reject)
[ "a", "b", "c" ].reject {|x| x>="b" } #=> ["a"]
[ "a", "b", "c" ].reject( function(i,x) {return x >=
"b" })](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-14-320.jpg)
![a = [ 4, 5, 6 ]
Array.zip
b = [ 7, 8, 9 ]
[1,2,3].zip(a, b) #=> [[1, 4, 7], [2, 5, 8], [3,
6, 9]]
[1,2].zip(a,b) #=> [[1, 4, 7], [2, 5, 8]]
a.zip([1,2],[8]) #=> [[4, 1, 8], [5, 2, nil],
var a = [ 4, 5, 6 ];
[6, nil, nil]]
var b = [ 7, 8, 9 ];
[1,2,3].zip(a, b) > [[1, 4, 7], [2, 5, 8], [3, 6,
9]]
[1,2].zip(a,b) > [[1, 4, 7], [2, 5, 8]]
a.zip([1,2],[8]) > [[4, 1, 8], [5, 2, null], [6,
null, null]]](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-15-320.jpg)
![Array.transpose
a = [[1,2], [3,4], [5,6]]
a.transpose #=> [[1, 3, 5], [2, 4,
6]]
var a = [[1,2], [3,4], [5,6]];
a.transpose() > [[1, 3, 5], [2, 4,
6]]](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-16-320.jpg)
![Array.rotate
a = [ "a", "b", "c", "d" ]
a.rotate #=> ["b", "c", "d", "a"]
a #=> ["a", "b", "c", "d"]
a.rotate(2) #=> ["c", "d", "a", "b"]
a.rotate(-3) #=> ["b", "c", "d", "a"]
var a = [ "a", "b", "c", "d" ];
a.rotate() > ["b", "c", "d", "a"]
a > ["a", "b", "c", "d"]
a.rotate(2) > ["c", "d", "a", "b"]
a.rotate(-3) > ["b", "c", "d", "a"]](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-17-320.jpg)
![Array.flatten
s = [ 1, 2, 3 ] #=> [1, 2, 3]
t = [ 4, 5, 6, [7, 8] ] #=> [4, 5, 6, [7, 8]]
a = [ s, t, 9, 10 ] #=> [[1, 2, 3], [4, 5, 6, [7,
8]], 9, 10]
a.flatten #=> [1, 2, 3, 4, 5, 6, 7, 8,
9, 10]
a = [ 1, 2, [3, [4, 5] ] ]
a.flatten(1) #=> [1, 2, 3, [4, 5]]](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-18-320.jpg)
![Array.sample
[1,2,3,4,5,6,7,8,9,10].sample() #=> 7 (just
randomly selected)
[1,2,3,4,5,6,7,8,9,10].sample(3) #=> 3, 9, 2](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-19-320.jpg)
![Array.shuffle
a = [ 1, 2, 3 ] #=> [1, 2, 3]
a.shuffle #=> [2, 3, 1]
var a = [ 1, 2, 3 ]; > [1, 2, 3]
a.shuffle() > [2, 3, 1]](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-20-320.jpg)
![Examples
(1..10).map{|i| ("a".."z").to_a[rand 26] }.join
new Array(10).map(function(i,item){
return
"abcdefghijklmnopqrstuvwxyz"[(26*Math.random()).floor()]
;
}).join("");
(10).times(function(i){
return
"abcdefghijklmnopqrstuvwxyz"[(26*Math.random()).floor()];
}).join("");](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-22-320.jpg)
![Examples
(1..10).map{|i| ("a".."z").to_a[rand 26] }.join
new Array(10).map(function(i,item){
return
"abcdefghijklmnopqrstuvwxyz"[(26*Math.random()).floor()]
;
}).join("");
(10).times(function(i){
return
"abcdefghijklmnopqrstuvwxyz"[(26*Math.random()).floor()];
}).join("");](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-23-320.jpg)
![What if we can write
and test like this
require '../src/com/ciphor/ruby/Array.js'
describe 'com.ciphor.ruby.Array', ->
testArray = null
beforeEach ->
testArray = [1, 2, 3, 4, 5]
Test for BDD -
Behaviour Driven
afterEach ->
testArray = null
Developement
it 'adds all elements in the given array into the self', ->
testArray.push_all [6, 7, 8]
expect(testArray.length).toEqual(8)
expect(testArray).toContain(8)](https://image.slidesharecdn.com/usefuljavascript-120719063027-phpapp01/85/Useful-javascript-26-320.jpg)
Useful javascript
- 1. Some Javascript useful perhaps
- 2. 他山之石，可以攻玉 Stones from other hills may serve to polish the jade of this one. advice from others may help one overcome one's shortcomings.
- 3. Ruby A Programmer’s Best Friend This time we use Ruby to polish our Jade.
- 4. Integer.times (10).times(function 10.times do |i| (i){ print i*10, " " print( i*10 + “ ”); end });
- 5. Number.step 1.step(10, 2) { |i| print i, " " } Math::E.step(Math::PI, 0.2) { |f| print f, " " } (1).step(function(i){ print(i); }, 10, 2); Math.E.step(function(f){ print(f); },
- 6. Number Object modulo abs ceil floor round step
- 7. String.capitalise "hello".capitalize #=> "Hello" "HELLO".capitalize#=> "Hello" "123ABC".capitalize#=> "123abc" "hello".capitalize() > "Hello" "HELLO".capitalize() > "Hello" "123ABC".capitalize() > "123abc"
- 8. String.each_char "hello".each_char {|c| print c, ' '} #=> "h e l l o " “hello”.each_char (function(c) {return c+” ”}) > “h e l l o ”
- 9. String.insert "abcd".insert(-3, 'X') #=> 'abXcd' "abcd".insert(-1, 'X') #=> 'abcdX' "abcd".insert(1, 'X') #=> 'aXbcd' "abcd".insert(-3, 'X') > 'abXcd' "abcd".insert(-1, 'X') > 'abcdX' "abcd".insert(1, 'X') > 'aXbcd'
- 10. String.reverse "Hello".reverse #=> "olleh" "Hello".reverse() > "olleh"
- 11. String Object casecmp insert each_char capitalise strip swapcase start_with end_with reverse
- 12. Array.each [1,2,3].each {|i| print i+5 } #=> 6 7 8 [1,2,3].each(function(i){ print( i+5) }) > 6 7 8 [1,2,3].reverse_each(function(i){ print( i+5) }) > 8 7 6 [{a:1,b:2},{a:2,b:3},{a:3,b:4}].each(function(item){ print(item.a+item.b) }) > 3 5 7
- 13. Array.map a = [ "a", "b", "c", "d" ] a.map {|x|x+"!" } #=> ["a!", "b!", "c!", "d!"] a #=> ["a", "b", "c", "d"] var a = [ "a", "b", "c", "d" ]; a.map(function(i,item){return x+”!”}) > ["a!", "b!", "c!", "d!"] a > [ "a", "b", "c", "d" ]
- 14. Array.remove_if (Array.reject) [ "a", "b", "c" ].reject {|x| x>="b" } #=> ["a"] [ "a", "b", "c" ].reject( function(i,x) {return x >= "b" })
- 15. a = [ 4, 5, 6 ] Array.zip b = [ 7, 8, 9 ] [1,2,3].zip(a, b) #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]] [1,2].zip(a,b) #=> [[1, 4, 7], [2, 5, 8]] a.zip([1,2],[8]) #=> [[4, 1, 8], [5, 2, nil], var a = [ 4, 5, 6 ]; [6, nil, nil]] var b = [ 7, 8, 9 ]; [1,2,3].zip(a, b) > [[1, 4, 7], [2, 5, 8], [3, 6, 9]] [1,2].zip(a,b) > [[1, 4, 7], [2, 5, 8]] a.zip([1,2],[8]) > [[4, 1, 8], [5, 2, null], [6, null, null]]
- 16. Array.transpose a = [[1,2], [3,4], [5,6]] a.transpose #=> [[1, 3, 5], [2, 4, 6]] var a = [[1,2], [3,4], [5,6]]; a.transpose() > [[1, 3, 5], [2, 4, 6]]
- 17. Array.rotate a = [ "a", "b", "c", "d" ] a.rotate #=> ["b", "c", "d", "a"] a #=> ["a", "b", "c", "d"] a.rotate(2) #=> ["c", "d", "a", "b"] a.rotate(-3) #=> ["b", "c", "d", "a"] var a = [ "a", "b", "c", "d" ]; a.rotate() > ["b", "c", "d", "a"] a > ["a", "b", "c", "d"] a.rotate(2) > ["c", "d", "a", "b"] a.rotate(-3) > ["b", "c", "d", "a"]
- 18. Array.flatten s = [ 1, 2, 3 ] #=> [1, 2, 3] t = [ 4, 5, 6, [7, 8] ] #=> [4, 5, 6, [7, 8]] a = [ s, t, 9, 10 ] #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10] a.flatten #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] a = [ 1, 2, [3, [4, 5] ] ] a.flatten(1) #=> [1, 2, 3, [4, 5]]
- 19. Array.sample [1,2,3,4,5,6,7,8,9,10].sample() #=> 7 (just randomly selected) [1,2,3,4,5,6,7,8,9,10].sample(3) #=> 3, 9, 2
- 20. Array.shuffle a = [ 1, 2, 3 ] #=> [1, 2, 3] a.shuffle #=> [2, 3, 1] var a = [ 1, 2, 3 ]; > [1, 2, 3] a.shuffle() > [2, 3, 1]
- 21. Array Object is_empty push_all size reverse_eachintersect clear each deduct map uniq union sample at shuffle values_attranspose contains last transpose keep_if compact select remove insert remove_if reject zip index rotate equals take remove_at fetchtake_while flatten count
- 22. Examples (1..10).map{|i| ("a".."z").to_a[rand 26] }.join new Array(10).map(function(i,item){ return "abcdefghijklmnopqrstuvwxyz"[(26*Math.random()).floor()] ; }).join(""); (10).times(function(i){ return "abcdefghijklmnopqrstuvwxyz"[(26*Math.random()).floor()]; }).join("");
- 23. Examples (1..10).map{|i| ("a".."z").to_a[rand 26] }.join new Array(10).map(function(i,item){ return "abcdefghijklmnopqrstuvwxyz"[(26*Math.random()).floor()] ; }).join(""); (10).times(function(i){ return "abcdefghijklmnopqrstuvwxyz"[(26*Math.random()).floor()]; }).join("");
- 24. How I simply try these snippets nodejs irb
- 25. Thanks to
- 26. What if we can write and test like this require '../src/com/ciphor/ruby/Array.js' describe 'com.ciphor.ruby.Array', -> testArray = null beforeEach -> testArray = [1, 2, 3, 4, 5] Test for BDD - Behaviour Driven afterEach -> testArray = null Developement it 'adds all elements in the given array into the self', -> testArray.push_all [6, 7, 8] expect(testArray.length).toEqual(8) expect(testArray).toContain(8)
- 28. Not The End