How let labview to verify string is in Scientific Notation.

[Bart_Aerts]

Hey all,

I want labview to convert a spreadsheet string to an array. This is easy using the 'spreadsheet string to array' tool. The only problem I've got is that I get the string from a RS232 device and it is time critical.

Example:

If I read the data from the buffer it gives me:

+1.50337800E+00,+1.70316300E+00 for two channels, this is converted and accepted

if there is a small delay I get:

+1.50337800E+00,+1.70316

This will also be accepted because +1.70316 is also recognized as a number.

How can program labview to check that every number it reads is according to the Scientific Notation?

Thanks

[GerdW]

Hi Bart,

maybe the problem is not with the string to number conversion?

The problem is your serial port handling!

You should always receive full messages - or otherwise don't use those mangled messages...

For your original question:

Convert to an array of strings (instead of numbers). Check each string to contain an "E" followed by a number...

[Bart_Aerts]

I know my problem is the serial port handling, but it is an old program, so I just wanted to make a check that all data is there, and if it isn't to make the log frequency slower.

My idea was also to check for the E's, but still something could go wrong there.
For Example:
+1.50337800E+10 is the value is wants to send but you only get +1.50337800E+1
this again results in a bad read value....

[GerdW]

Hi Barts,

check for the delimiter "," to be the last char and throw away any string parts after the last delimiter...

When there is a clear scheme for the last number (like ±n.nnnE±mm) you can check for that pattern using some RegEx pattern matching. Wait for one of the RegEx experts here to jump in...

[Don_Phillips · Accepted solution]

This regex seems to work for me for all the cases I tried:

[+/-]\d+\.\d+[Ee][+/-]\d+

Note that it is very restrictive and only follows the form of ±n.nnnE±mm

[billko]

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@Don_Phillips wrote:

This regex seems to work for me for all the cases I tried:

[+/-]\d+\.\d+[Ee][+/-]\d+

Note that it is very restrictive and only follows the form of ±n.nnnE±mm

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If it was up to me, I'd fix the problem and not the symptom - but many times, it is NOT up to me.  MANY times there are artificial constraints (like the time allocated to fix the problem) so you just have to make a band-aid like this.  I get grumpy when I'm forced to program a workaround instead of a fix.  😉