ruby math functions

Hi all,

Here i have listed some of the most frequently used math functions in ruby.

round method rounds the value
if decimal value is less than .5, rounded to its lowest value
irb(main):006:0> 1.2.round
=> 1
if decimal value is greater than .4, rounded to its highest value
irb(main):007:0> 1.5.round
=> 2

floor method rounded the value to lowest value
irb(main):008:0> 1.5.floor
=> 1

ceil method rounded the value to next highest value
irb(main):009:0> 1.5.ceil
=> 2

'nan' method used to check whether the value is integer or not
irb(main):010:0> x = 0.0/0.0
=> NaN

irb(main):011:0> x.nan?
=> true

Get ASCII value
irb(main):017:0> Integer(?e)
=> 101

irb(main):018:0> Float(?e)
=> 101.0

>> "%.2f" % (1.0/2.0)
=> "0.50"

The last method is mainly used for display purpose. We have to display the floating point number in any page(say to display the cost) we must modify the output in such a way to get clear display(Max of 2 numbers after decimal point in this case).


Thanks,
Vadivelan

Some more uses of '$' in prototype javascript

Hi all,

We are all using the '$' in prototype javascript to get the object of the matched DOM element by using id of the element.

Say for example:

the page has the div element

content inside the div element

To get the object of the div element we are using the '$'.

$('container') => returns the object of the DOM element.

$A/$W/$F => are also available but rarely used..

the below lines explain the use of the $A/$W/$F

// converts a string into array, each element is taken as a count
>>> $A('1')
['1']
>>> $A('123')
["1", "2", "3"]

// converts a string into array, it takes whitespace as delimiters
>>> $w('1 2 3')
["1", "2", "3"]

// used to get values of text field which is located inside any forms
// same as Form.Element.getValue
>>> $F('press_room_url')

So start using these commands makes the code simpler..


Thanks,
Vadivelan