Module 05 - Common Functions
Lesson 01 - Type Manipulation
Next up is type manipulation. Sometimes, you have variables stored as one type, and you need to convert them to another.
First of all, the GETTYPE function. You can use GETTYPE to check what type a variable is. It takes one argument, which is the variable which you want to check the type of.
It will return 1 for integers, 2 for real numbers, 3 for strings, and 4 for arrays. 0 means an internal error occurred.
OnGetType
{
_some_string = "123.4"
GETTYPE(_some_string)
}
Click to run the above code in the Ghost Guides companion ghost.
The above function will return 3
Now, what if we wanted that string to be an integer instead, so we could do math with it? TOINT is a function that takes a single argument, and attempts to convert it into an integer. If it fails, because the data it was given cannot be converted, it will output 0. Otherwise, it will output the new integer.
Note that if you give it a real number, anything after the decimal point will be lost.
OnConvertToInt
{
_some_string = "123.4"
_some_string = TOINT(_some_string)
_some_string += 2
_some_string
}
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The output of the above function will be 125
TOREAL is much the same, but it converts other data types to real numbers. It will return 0.000000 if it fails.
OnConvertToReal
{
_some_string = "123.4"
_some_string = TOREAL(_some_string)
_some_string -= 0.2
_some_string
}
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The output of the above function will be 123.200000
There is also TOSTR, which converts other data types to strings. If TOSTR fails, it will return nothing.
OnConvertToString
{
_some_int = 123
_some_int += 2
_some_int = TOSTR(_some_int)
_some_int += "!"
_some_int
}
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The output of the above function will be 125!
Note that TOSTR can also be used to convert a general purpose array to a simple array separated by commas.
OnConvertArrayToString
{
_colors = ("red","blue","green")
_colors = TOSTR(_colors)
GETTYPE(_colors)
}
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The above function will output 3 (General purpose arrays and simple arrays look the same when output to a ghost’s balloon, so it is easier to show this change with GETTYPE.)
Finally, there is SPLIT. SPLIT converts a string to a general purpose array, by splitting up the string into different elements. You must specify which character/string it should split on (the character that the simple array is using as the delimiter). It takes 2 arguments; the string to split, and which character it should split on.
OnConvertStringToArray
{
_colors = "red,blue,green"
_colors = SPLIT(_colors,",")
GETTYPE(_colors)
}
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The above function will output 4
Further Context
Changing the types of variables isn’t something you usually want to do too often. At least when global variables are involved, it’s important to have them consistently be the same type. But sometimes, you do need to switch things around. Particularly references, and especially if you have auto type convert off (we’ll cover that later). It is also very important for multidimensional arrays, if you are storing numbers in them, since the arrays can only actually hold information as strings.
SPLIT and TOSTR for arrays is also very important. As mentioned previously, sometimes you need to make a general purpose array into a simple array, to avoid the nesting behavior. Or maybe you’re working with part of a multidimensional array, and you really need it to be a general purpose array while you’re modifying its elements.
OnEditMultiArray
{
_array = "A|1,B|2,C|3"
_to_change = SPLIT(_array[1],"|")
_to_change[1] = IARRAY
_array[1] = TOSTR(_to_change)
_array
}
Here’s a modified version of an example used back in the arrays module. You can see that this time, I use SPLIT and TOSTR to convert it to a general purpose array (so I can use IARRAY) and then back again.