This should be quite simple for the experts.
How do I extract the value 2.11 from this string !IR1= -2.11:24
OR
extracting 3.27 from this strong !IR1= 3.27:88
Thank you!
Regards,
Prof
This shows how to use Scan From String to get at the value you want. Note that there's a space between the open square bracket and the hyphen. This matches any number of spaces and/or hyphens between the text !IR1= and the numeric value.
This image is a VI snippet so you should be able to drag it right on to your LabVIEW diagram and use the code.
If you right-click on Scan From String and choose 'Edit Scan String' you get this dialogue:
which helps you to assemble the scan string you want. Note that it puts spaces in between each of the scan items by default, which you may not want. To get more help on constructing scan strings, see the LabVIEW help for Scan From String.
When scanning a Real number I always recommend to explicitly specify the decimal separator character in the format string.
Using the vi Programming/String/Scan From String you should use a format string like %.;!IR1= %f.
String %.; at the beginning of the format string tells LabVIEW that your decimal separator is a dot (.), independently from Format settings of your OS or in LabVIEW.
Not specifying this decimal separator is a common mistake that could lead to unexpected results if you plan to use your code in several computers.
Related
I have a Python script which collects data and sends it to my MySQL table.
I noticed that the "Cost" sometimes is 0,95 which results in 0 in my table since my table use "0.95" instead of "0,95".
I assume the best solution is to convert the , to . in my Python script by using:
variable.replace(",", ".")
However, couldn't one solution be to change format in my MySQL table? So that I store numbers in this format:
1100
0,95
0,1
150000
My Django Model
cost = models.DecimalField(max_digits=10, decimal_places=4, default=None)
Any feedback on how to best solve this issue?
Thanks
Your first instinct is correct: convert the "unusual" (comma-decimal) input into the standard format that MySQL used by default (dot-decimal) at the first point where you receive it.
there's lots of ways to write numbers
Be careful, though that you don't get stung by people using commas as thousands separators like "3,203,907.23", or the European form "3.203.907,23", the Swiss "3'203'907,23' or even this form, which is widely used in India: "32,03,907.71" (yes, I did mean to type only two digits there!)
To make your life easier, the rule for currencies is relatively simple:
where a dot or comma is followed by only two digits at the end of the string, that character is acting as the decimal separator.
Once you know which is the decimal separator, you can safely remove all other non-digits from the string, change the decimal separator you found to . then use any standard library string-to-number conversion.
Storage format isn't presentation format
Yes, you can tell MySQL to use comma as its decimal separator, but doing that will break so much of your code - including the parts of the framework that read from the database and expect dot-decimal numbers - that you'll regret doing it that way very quickly...
There's a general principle at work here: you should do your data storage and processing using a format that is easy to process, interchangeable with other systems, and understood by other software developers.
Consider what happens if you need to allow a different framework to access your MySQL database to generate reports... whoever develops that software (and it may be you) will be glad that the numbers are all stored the way numbers are "always" stored in databases.
Convert on the way in, re-convert on the way out
Where you need to accept input in a different format, convert that input into your standardised format as early as possible.
When you need to use an output format, do the conversion to that format as late as possible.
The idea is to keep as much of your system "unexceptional" as possible. A programmer who has to remember what numeric format will in force at the time when a given method is called is not a happy programmer.
P.S.
The option you're talking about in MySQL is an example of this pattern: it doesn't change how numeric data is stored. All that changes is how you pass numbers to MySQL and how it presents them back to you.
I have a json string which contains a long number but in scientific notation (like 1.559101974041E12 instead of 1559101974041). Due to this, I am not able to parse it using ?eval as this value must be in double quotes in order to get parsed.
I thought of one solution like putting double quotes around them using regex and get them evaluated. After that, use some free marker method to convert value into long. But this solution is very risky and can alter other values as well.
I'm not sure how your template looks, but if you have variable s that contains the string "1.559101974041E12" (the quotation marks aren't part of the string value itself), then you can parse it like s?number. s?eval doesn't work because scientific notation is not part of the FreeMarker syntax (but ?number can parse more formats).
If you will re-print the number in the template, note that depending on locale and configuration settings, it might will look like 1,559,101,974,041. You can prevent that with ?c (for example like ${s?number?c}), in which case it will always look like 1559101974041.
I have the following text strings:
"Name":"John"}]
"Age":36
"Address":"ABC,PQR234[]/.,#ANYCHARACTERS"
"Gender":null
I need to get two groups (key value pair) from this such that the output would be only:
Key|Value
Name|John
Age|36
Address|ABC,PQR234[]/.,#ANYCHARACTERS
The requirement is to have a single regex to grab everything in the double quotes if the double quotes are present. If not, take the value without the quotes.
In our example above, 36 and null are the one without the quotes and they need to be captured as well.
I have tried a lot but have failed to do so.
UPDATE:
I don't know why I am getting down votes for this question. Yes this is JSON that I am trying to parse but there is a reason behind why I am doing this and not using any document parser.
I am supposed to use Talend for getting a dynamic JSON converted into Key Value Pair. What I mean by dynamic is the fields of the JSON can vary and hence I do not have a fixed schema and hence cannot use a document parser (which demands a fixed structure of JSON). I am devising a solution to get around this using Normalizer (on comma) and then extracting the key value pair which will be in double quotes using Regular Expressions. I tried many things on my own and since I am not an expert in Regular expressions, I have come here to get inputs.
If you know any better solution to this, I would be very happy to get your inputs.
How about this?
/"?([^\n"]*)"?:"?([^\n"]*)"?/
Explained in detail at:
https://regex101.com/r/UM0rl2/1/
I am trying to use a *.resw file in my UWP app to store localized strings. I am loading these strings through ResourceLoader.GetString() and am placing them in a MessageDialog for presentation to the user, but no matter what I do the return value of GetString() is an empty (zero-length) string. I am following the SDK sample for localization, but am not getting the expected response.
The string I am trying to use is of the format InvalidAssemblyDialog.Message.
As it turns out this problem was due to my using dots in the keys for my strings in the *.resw file. Dots are reserved, and my usage of them was causing name-resolution errors. In the case of the example above, I changed it to InvalidAssemblyDialog_Message.
Here the documentation says "." characters should be replaced with "/" when resources are queried from code.
If a resource name is segmented (it contains "." characters), then replace dots with forward slash ("/") characters in the resource name. Property identifiers, for example, contain dots; so you'd need to do this substition in order to load one of those from code.
I am trying to create a regex to validate usernames which should match the following :
Only one special char (._-) allowed and it must not be at the extremes of the string
The first character cannot be a number
All the other characters allowed are letters and numbers
The total length should be between 3 and 20 chars
This is for an HTML validation pattern, so sadly it must be one big regex.
So far this is what I've got:
^(?=(?![0-9])[A-Za-z0-9]+[._-]?[A-Za-z0-9]+).{3,20}
But the positive lookahead can be repeated more than one time allowing to be more than one special character which is not what I wanted. And I don't know how to correct that.
You should split your regex into two parts (not two Expressions!) to make your life easier:
First, match the format the username needs to have:
^[a-zA-Z][a-zA-Z0-9]*[._-]?[a-zA-Z0-9]+$
Now, we just need to validate the length constraint. In order to not mess around with the already found pattern, you can use a non-consuming match that only validates the number of characters (its literally a hack for creating an and pattern for your regular expression): (?=^.{3,20}$)
The regex will only try to match the valid format if the length constraint is matched. It is non-consuming, so after it is successful, the engine still is at the start of the string.
so, all together:
(?=^.{3,20}$)^[a-zA-Z][a-zA-Z0-9]*[._-]?[a-zA-Z0-9]+$
Debugger Demo
I think you need to use ? instead of +, so the special character is matched only once or not.
^(?=(?![0-9])?[A-Za-z0-9]?[._-]?[A-Za-z0-9]+).{3,20}