DZone Snippets: array code

Array#replace_pattern

farleyknight (Farley Knight) — Sun, 13 Jul 2008 19:36:38 GMT

# If you are treating Arrays like s-expressions, you might want to replace a particular pattern.



Array.class_eval do

  def replace_pattern(pattern, value)

    copy = self.dup

    (0..copy.length).each do |i|

      if copy[i] == pattern

        copy[i] = value

      elsif copy[i].is_a? Array

        copy[i] = copy[i].replace_pattern(pattern, value)

      end

    end

    copy

  end

end

foreach like syntax in JavaScript

jeffreybarke (Jeffrey Barke) — Sat, 12 Jul 2008 23:54:19 GMT

From justsomeguy's post to http://forums.invisionpower.com/lofiversion/index.php/t168975.html:

Since all JavaScript objects are really just associative arrays, there is a "foreach" like syntax for the "for" construct. Without it, it would be very hard to work with many common JavaScript objects. It's actually very simple to use and incredibly useful if you like associative arrays.



//this is safe only if you can assure object has not been extended.

var array = new Object();

//use the below if Object has been extended

var array;

//everything below here works fine regardless of the two above cases

array['something'] = 'foo';

array['somethingelse'] = 'bar';

for (keyVar in array) {

   alert(keyVar + '--' + array[keyVar]);

}

Extending Array Prototype

demods () — Thu, 10 Jul 2008 08:37:08 GMT

Extending array prototype with sum, minimum, maximum and remove



Array.prototype.sum = function(){

	for (var i=0, sum=0; i < this.length; sum += this[i++]);

	return sum;

}

Array.prototype.max = function(){

	return Math.max.apply({},this)

}

Array.prototype.min = function(){

	return Math.min.apply({},this)

}

Array.prototype.remove=function(s){

	for (i=0; i < this.length; i++){

		if (s == this[i]) this.splice(i, 1);

	}

}

Converting a numerical string into an array

jrobertson (James Robertson) — Sun, 29 Jun 2008 19:35:02 GMT

irb(main):097:0> c = "080629".scan(/\d\d/)
=> ["08", "06", "29"]

Split array or string into smaller arrays

santiago.aguiar (Santiago Aguiar) — Fri, 13 Jun 2008 19:37:23 GMT

Splits an array or string into smaller arrays of the given size. Inspired on the ruby one ;).



import math

# v = value to split, l = size of each chunk

f = lambda v, l: [v[i*l:(i+1)*l] for i in range(int(math.ceil(len(v)/float(l))))]

Example



>>> f('000000111111222222333333444444567', 6)

['000000', '111111', '222222', '333333', '444444', '567']



>>> f(tuple('000000111111222222333333444444567'), 6)

[('0', '0', '0', '0', '0', '0'), ('1', '1', '1', '1', '1', '1'), ('2', '2', '2', '2', '2', '2'), ('3', '3', '3', '3', '3', '3'), ('4', '4', '4', '4', '4', '4'), ('5', '6', '7')]

Long live python :). Of course, a lisp/haskell implementation probably blows this snippet out.

convert a 1D array wave file to a stereo 2D array

tiskevin (tiskevin) — Tue, 20 May 2008 12:30:44 GMT



    private int[][] zetOmNaarStereoStream(byte[] arrbBuffer){

        int lengte = arrbBuffer.length / 4;

        int[][] arriUitvoer = new int[2][lengte];

        for (int iTeller=0 ; iTeller            //Linker kanaal

            arriUitvoer[0][iTeller] = (arrbBuffer[((iTeller * 4) + 0)] & 0xFF) | (arrbBuffer[((iTeller * 4) + 1)] << 8);

            //Rechter kanaal

            arriUitvoer[1][iTeller] = (arrbBuffer[((iTeller * 4) + 2)] & 0xFF) | (arrbBuffer[((iTeller * 4) + 3)] << 8);

        }

        return arriUitvoer;

    }

Open an arbitrary number of resources safely in ruby

tunah (Sam McCall) — Tue, 22 Apr 2008 00:44:04 GMT

I'm too lazy to work out what happens if I try filenames.map {|f| File.open(f) } and the thirteenth file doesnt exist, but I bet I don't like it.

module Enumerable

  # Example:

  # ['a','b'].with_files {|f,g| ... }

  # is the same as

  # File.open('a') {|f| File.open('b') {|g| ... } }

  # You can specify modes with

  # [['a', 'rb'], ['b', 'w']].with_files ...

  def with_files(

      meth = File.method(:open),

      offset=0,

      inplace=false,

      &block

  )

    if inplace then

      if offset >= length then

        yield self

      else

        fname,mode = *self[offset]

        File.open(fname,mode) {|f| 

          self[offset] = f

          self.with_files(meth,offset+1,true,&block)

        }

      end

    else

      dup.with_files(meth,offset,true,&block)

    end

  end

end

Array#pad!

nicwilliams (Dr Nic Williams) — Mon, 07 Apr 2008 10:44:20 GMT

My ri docco says there is an Array#pad! but runtime Ruby says there isn't. Bah. So I wrote one:



class Array

  def pad!(expected_length, pad_item = nil)

    while expected_length > length

      self << pad_item

    end

    self

  end

end

Concat two array

rcube9 (rajesh) — Wed, 02 Apr 2008 03:03:45 GMT

var sNames:Array = ["Rajesh","Buvanesh","Latha","Ramesh"];
var sPhones:Array = ["9940350708","00000000","044-42151184","9841026070"];

for (var i=0;i trace(sNames[i]);
trace(sPhones[i]);
}

Array.push

rcube9 (rajesh) — Wed, 02 Apr 2008 03:03:06 GMT

var sEmployees:Array = [];
sEmployees.push(["Ramesh","9841026070"]);
sEmployees.push(["Rajesh","9940350708"]);
sEmployees.push(["Latha","044-42151184"]);
sEmployees.push(["Buvanesh","000-0000000"]);

for (var i:Number=0; i trace("Name:" + sEmployees[i][0]);
trace("Phone:" + sEmployees[i][1]);
}