User:Eleanorg/Prototyping Yr 1 Timester 1/Cookbook: Percentages: Difference between revisions

Revision as of 17:41, 30 November 2011

Here are some examples of cool things you can do by grabbing numbers from the internet, and converting them into percentages. Once you've converted your number into a percentage, you can do more things with it - for example, using it to determine CSS styles. (Conversion to % also has the added benefit of making your randomly scraped data seem "scientific".)

Grabbing a number

Here is a basic way to extract a number live from a website - in this case, the current longitudinal position of a ship.

(coming soon)

Converting to a % value

In this example, I convert the ship's current position into a % distance from its destination. First, establish the ship's starting point (001.2528), and its destination (004.1285). These will act as 0% and 100% respectively. The percentage is worked out based on the ship's current position within this range.

import re
 
### convert longitude into 5 digit integer
longitude = str(001.2528) 			# must be a string for regex to work
longint = int(re.sub("\.", "", longitude)) 	# removes decimal point and converts back to an integer
 
### convert integer into percentage of given range
# converts longitude into a percentage, where 001.2528 = 0% and 004.1285 = 100%
# range between numbers is 28703, so 1% of range is 28703/100 ---> 287.03. Longitude equivalent to 1% will be 12528 + (28703/100)
# thus to convert longitude to percentage, work out its distance from 12528 and divide this distance by 287.03.
percent = int((longint - 12528) / 287.03)       # convert to int to avoid nasty decimals
percentstr = str(percent)                       # now convert to a string, for use in html etc.

Using % value in CSS Styling

Here, we use our % value to determine the size of a div in an html document:

print "Content-Type: text/html"
print
print """
  <html>
    <body>
       <div style="width:""" + percentstr + """%; height:""" + percentstr + """%; background-color: #ddd;">
         <p>""" + percentstr + """</p>
       </div>
    </body>
  </html>""

Here, we use the % value to change the opacity of an image:

(coming soon)

@@ Line 29: / Line 29: @@
 ===Using % value in CSS Styling===
-Here, we use our % value to determine the size of a <div> in an html document:
+Here, we use our % value to determine the size of a div in an html document:
 <source lang=python>