Strings, File I/O, Shift Register

string

a sequence of displayable or non-displayable (ASCII) characters

string subset

-Returns the substring beginning at offset and containing length number of characters

-the first character is at offset zero

-Unprintable characters should be counted when determining the length input

String functions timeline

-Returns the matched substring

-the function searches for regular expression in the string input

-If it finds a match, the string is split into three parts:  

  •the match

  •the string before the match

  •the string after the match.

-When no match is found, offset past match returns a -1.

Build string express

function that converts inputs that are not a string into a string

Converting Strings to Numerics

-Converts the input string containing valid numeric characters to individual numbers.

-Format string can specify multiple outputs with differing data types (numeric, Boolean, etc.).

-The function can be stretched out to add more output terminals.

File Input and Output

can be done in LabVIEW using VIs and functions

string functions (2)

used to edit and manipulate strings on the block diagram

Scan From String function

used to convert a string to a numeric.

creating or editing a format string

Right-click the Format Into String or Scan From String function and select Edit Format String or Edit Scan String from the shortcut menu

to handle all aspects of file I/O

Use the File I/O VIs and functions

When writing and reading a file

you open, create, or replace a file, write the data, and close the file

To access a file through a dialog box

do not wire file path in the Open/Create/Replace File VI

To write data to a spreadsheet file

you must format the string as a spreadsheet string, which is a string that includes delimiters, such as tabs. Use the Format Into File function to format string, numeric, path, and Boolean data as text and write the text to a file

Shift registers

transfer data values from one iteration to the next