Searches a string for the next token, where a token is defined as either the next set of characters that appears before a specified delimiter or as one of a specified set of operators.
A Boolean value that determines whether an empty token exists between consecutive delimiters.
|True||The node returns an empty string as the token string when it encounters a pair of consecutive delimiters.|
|False||The node considers consecutive delimiters to be a single delimiter and therefore never returns an empty string as a token.|
The string to scan for tokens.
The number of characters into the input string at which this node begins its operation.
An array of strings that this node identifies as tokens when they appear in input string, even if they are not surrounded by delimiters.
Available Format Specifiers
|%d||match decimal integer|
|%o||match octal integer|
|%x||match hexadecimal integer|
|%b||match binary integer|
|%e, %f, %g||match floating-point or scientific real number|
|%%||match a single % character|
An array of strings that act as separators between tokens. The node does not return these strings as tokens but instead uses these strings to determine where tokens begin and end.
Default: White space characters — space, tab, linefeed, and carriage return
A Boolean value that determines whether the node uses saved values for delimiters and operators, thereby improving string parsing performance.
Set this input to True only if delimiters and operators have not changed since the last time this node executed.
|True||The node uses the delimiters and operators from the most recent time this node executed.|
|False||The node uses the values wired to delimiters and operators.|
Improving Execution Speed
To optimize performance of this node, use the recommendations in the following table:
|You execute token string for the first time.||Set the initial value to False. Set the initial value to True each subsequent time as long as operators and delimiters have not changed.|
|operators and delimiters do not change during the execution of the loop.||To ensure correct behavior, use a shift register with True and False constants as shown in the following diagram.|
|You wire both operators and delimiters to diagram constants or leave them both unwired.||You can leave use cached delimiter/operator data? unwired and still achieve optimal performance.|
The same string as input string, unchanged.
The index in the input string of the first character following the token and any trailing delimiters.
If the offset is less than 0 or greater than the number of characters in the input string, or if the end of the string was reached, this output is -1.
To continue searching for more tokens in the input string, use this value as the offset the next time you call this node.
The first token in the input string following the offset. This output is either all text that appears between two delimiters or one of the strings specified by operators.
The index of the token string in operators if the token string matches any of the elements in operators.
If token string is any other string, this output returns -1. If the node reaches the end of the input string without finding any valid operator, this output returns -2.
Tokens are text segments that typically represent individual keywords, numeric values, or operators found when parsing a configuration file or other text-based data format. You can specify tokens with the data you pass into the node through the delimiters and operators inputs. For example, because the space character is a delimiter by default, each word of This is a string is a token, and you can parse the sentence into its component words.
You can use this node in a While Loop to scan multiple tokens. Refer to Parsing a String into Smaller Pieces for more information.
If a portion of the input string matches more than one defined operator, the node chooses the longest match as a token. For example, if >, =, and >= are defined operators, the input string 4>=0 produces >= as the next token string with an offset of 1.
If you want to interpret a series of digits as a token that represents a number, include a format specifier in the list of values for the operators input. For example, including %b as one of the elements in operators causes the node to interpret a string of 1s and 0s as a binary number and return it as a token after encountering any character that is not a 1 or 0.
If you include a format specifier in operators along with the strings + or -, the node does not recognize leading, or unary, + and - signs. The node always returns them as separate tokens. For example, if input string contains -5 and operators includes [%d, -] , token string returns [-, 5] instead of [-5] . This is an exception to the "longest match" rule.
Characters in UTF-8 can be multiple bytes so string nodes count the number of characters in a string instead of jumping to a point in memory. Since the length and offset parameters are in units of characters, avoid nesting this node with large strings because that can create exponential functions that carry a higher performance burden.
If you place the node in a While Loop, the node returns the following values.
|input string||operators||delimiters||token string||Comments|
|4>=0||[>, =, >=]||\s, \t, \r, \n (default)||[4, >=, 0]||
If a portion of the input string matches more than one defined operator, Scan String for Tokens chooses the longest match as a token.
|[==, !=]||\s, \t, \r, \n (default)||[a, ==, b, c, !=, d]|
|G2 X0.5Y1.0 i0.5j0 z-0.05||[X, Y, Z, i, j, z]||\s, \t, \r, \n (default)||[G2, X, 0.5, Y, 1.0, i, 0.5, j, 0, z, -0.05]||
This is an example of a string of G-code, a language commonly used for machine control. This string describes a circle.
C, _ (add to
\s, \t, \r, \n (default)
|[1, 1.11, 2, 2.22, 3, 3.33]||
This is an example of a string from a DAQ log with three channels.
Where This Node Can Run:
Desktop OS: Windows
FPGA: DAQExpress does not support FPGA devices
Web Server: Not supported in VIs that run in a web application