Strings are collections of characters.

Operations can be used on strings as well as numbers. Example 1 shows the concatenation (joining) of two strings using the + operator.

Example 1
"abc" + "def"   # "abcdef"


Strings can be represented as arrays of characters, and we can index them starting from 0.

Diagram 1 shows how the string "Hello, World!" is indexed.

Diagram 1

Table 1 shows the string manipulation functions in pseudo-code.

Table 1

Function	Description	Example	Result
LEN	Length: returns the number of characters in a string.	LEN("Hello, World!")	13
POSITION	Returns the index of the first occurrence of a character in a string.	POSITION("Hello, World!", 'o')	4
SUBSTRING	Returns the part of the string from the start index to the end index.	SUBSTRING(3, 7, "Hello, World!")	"lo, W"

ASCII is a code which assigns each character a unique number. It will be explained further in 3.05 (ASCII and Unicode).

Table 2 shows the ASCII functions in pseudo-code.

Table 2

Function	Description	Example	Result
CHAR_TO_CODE	Converts a character to its ASCII value.	CHAR_TO_CODE('A')	65
CODE_TO_CHAR	Converts an ASCII value to its character.	CODE_TO_CHAR(65)	'A'

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What is the output of SUBSTRING(POSITION(a, 'l'), LEN(a)-1, a) when a = "Hello"?

"llo"

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