You use subString in OCL to extract a specified, inclusive range of characters from a String.

Syntax

string.subString(lower, upper)

subString returns the characters in string from position lower through position upper. Both positions are included in the result.

Syntax:

string.subString(lower : Integer, upper : Integer) : String

Parameters and result

Item	Type	Description
lower	Integer	The first character position to include. Positions are 1-based: the first character is position 1.
upper	Integer	The last character position to include.
Result	String	A new string containing every character from lower to upper, inclusive.

Valid bounds

Both arguments must be within the string's character positions:

1 <= lower
lower <= upper
upper <= string.size()

Use size() to obtain the number of characters in a string. subString is a String operation; a String is not a collection of characters. See Documentation:String for the distinction.

Examples

Here are several examples demonstrating subString in action:

Expression	Result
'substring operation'.substring(11, 19)	'operation'
'substring operation'.substring(1, 1)	's'
'substring operation'.substring(0, 1)	invalid

Extract the first word

In 'Hello World', the characters in Hello occupy positions 1 through 5.

'Hello World'.subString(1, 5)

Result:

'Hello'

Example: Extract First Word

'Hello World'.subString(1, 5)

Result:

Hello

Extract a word after a space

The word World occupies positions 7 through 11. The space at position 6 is not included.

'Hello World'.subString(7, 11)

Result:

'World'

Extract one character

Use the same position for both bounds when you need one character.

'Hello'.subString(2, 2)

Result:

'e'

Extract through the end of a string

Use size() as the upper bound when the extracted text should continue to the final character.

let text : String = 'Order-123' in
  text.subString(7, text.size())

Result:

'123'

Invalid positions

Do not use position 0: indexing starts at 1.

'Hello'.subString(0, 2)

This is invalid because lower is outside the allowed range.

The following bounds are also invalid:

• lower is greater than upper, for example 'Hello'.subString(4, 2).
• upper is greater than the string length, for example 'Hello'.subString(2, 6).

When you need to test whether known text occurs in a string rather than extract a range, use Contains. When the split point follows a pattern rather than fixed character positions, use regExpSplit.

Invalid Index:

'substring operation'.subString(0, 1)

Result:

Invalid/Error

Index 0 is invalid (must start at 1)

See also

• Documentation:String
• Documentation:OCLOperators Size () : Integer
• Documentation:OCLOperators length
• Documentation:OCLOperators Contains
• Documentation:OCLOperators ToCharArray