Flash MX 2004 Games : Art to ActionScript

Flash MX 2004 Games
Extracting a letter from a string
Line 5 uses the method ‘charAt’ to extract a single letter from the string, ‘person’. The number in
the brackets is a parameter passed to the method, the index of the letter to extract, starting with
zero as the first letter from the left. The letter with index 2 in ‘Steve’ is the first ‘e’.
Extracting a section from a string
Another useful method is ‘substr’; this takes two parameters, first where to start extracting as an
index and the second the number of characters to extract. Using the parameters 4 as the index and
6 as the length from the string, ‘desc’, gives the sub-string ‘winner’.
Dividing up a string
The method ‘split’ can be used to divide a string into separate letters or words. It takes a single
parameter, in this example we use‘’(asingle space). The return value is a list of all the words that
we can display, separated by commas using the trace command as shown in line 7.
Finding a string inside another
Line 8 shows how to search through a string to find another. It returns either the index to the
sub-string or -1 if the sub-string cannot be found.
Getting the code value of a character
Characters in a string are given code values based on the ASCII character codes. You can find a
table of codes at http://www.asciitable.com/. Line 9 shows how this can be done.
Setting a character using the code value
Line 11 shows how you can use the method ‘fromCharCode’ which takes a single parameter, the
ASCII code and returns a string. In this example using the ASCII value 65 returns a capital letter A.
Converting case
The string object contains methods to convert the entire string to either upper (toUpperCase) or
lower (toLowerCase) case.
Although strings are usually used to store textual information, they can be useful to store more
complex data in a very compact way. For example the string
W12U6T
could be used to represent walk forward 12 paces (W12), then up 6 steps (U6) and finally turn (T).
A simple code reader could extract this information using the string methods. In this way you
could create complex new actions using a simple code formula.
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