We Keep Coding

Finding specific parts of strings containing certain letters/symbols and then creating a reference to those parts

Currently I am storing data in form of jsons (strings) on a database. As jsons contain quotation marks though and the database I am using is unable to store quotation marks in this form: " it converts all quotation marks (like this one :") to "
Unity will therefor not allow me to deserialize the json anymore as it now looks somewhat like this:
{"coins":0,"level":0,"kills":0,"deaths":0,"xp":0.0}
instead of like this:
{"coins":0,"level":0,"kills":0,"deaths":0,"xp":0.0}
Obviously a possible solution to this would be to find all the parts of my json string containing ", storing a reference to these parts and then converting all of those parts to a simple "
Therefore I would ask you how I would go about doing this.

You can use String.replace(""","\"") and than String.split, but maybe you need to think about moving to a database that supports JSONs, like mongodb. Other direction to solve this: have you tried placing the " as \"?

The Database is doing a good job by encoding the text for you thereby preventing Hacks!! It is simply doing text encoding for you.
All you have to do is Decode the text before using it. If there are chances that double quote is part of the data then you should be careful while reverse converting the encoded text. Refer to this MSDN resource Anti-Cross Site Scripting Library to get better insight into topic

Reverse RegExp from user entered string ( C#)

Is it possible to generate regular expressions from a user entered string? Are there any C# libraries to do this?
For example a user enters a string e.g. ABCxyz123 and the C# code automatically generates [A-Z]{3}[a-z]{3}\d{3}.
This is a simple string but we could have more complicated strings like
MON-0123/AB/5678-abc 2/7
Or
1234-678/abc::1234ABC?246
I already have a string tokeniser (from a previous stackoverflow question) so I could construct a regex from the list of tokens.
But I was wondering if there is a lib or C# code out there that’ll do it.
Edit: Important, I should of also said: It's not the actual character in the string that are important but the type of character and how many.
e.g A user could enter a "pattern" string of ABCxyz123.
This would be interpreted as
3 upper case alphas followed by
3 lower case alphas followed by
3 digits
So other users (when complied) must enter strings that match that pattern [A-Z]{3}[a-z]{3}\d{3}., e.g. QAZplm789
It's the format of user entered strings that's need to be checked not the actual content if that makes sense

Jerry has a related link
creating a regular expression for a list of strings
There are a few other links off this.
I'm not trying to do anything complicated e.g NLP etc.
I could use C# expression builder and dynamic linq at a push, but that seems overkill and a code maintainable nightmare .
I'll write my own "simple" regex builder from the tokenized string.
Example Use Case:
An admin office user where I work could setup the string patterns for each field by typing a string pattern, My code converts this to a regex, I store these in a database.
E.g: Field one requires 3 digits at the start. If there are 2 digits then send to workflow 1 if 3 then send to workflow 2. I could simply check the number of chars by substr or what ever. But this would be a concrete solution.
I am trying to do this generically for multiple documents with multiple fields. Also, each field could have multiple format checkers.
I don't want to write specific C# checks for every single field in numerous documents.
I'll get on with it, should keep me amused for a couple of days.

How to validate a excel expression programmatically

I have been developing an application that one of it's responsability is provide to user an page that it's possible to write math expression in EXCEL WAY.
It is an application in ASP.NET MVC, and it's use the SpreadSheetGear library to EXECUTE excel expression.
As it's show below, The page has an texarea to write expression and two button on the right. The green one is for VALIDATE THE EXPRESSION and the red one is for clean textarea.
A,B,C are parameter, that application will replace for values. Notice that it is not possible to know the parameter data type. I mean, if I write a concatenate function, It is necessary that user use double quotes (") to delimitate string. For example
CONCATENATE("A","B") thus, is necessary that user KNOW functions parameters and its correlate data types.
My main issue is how to validate the expression?
SpreadSheetGear there isn't any method to perform this validation.
The method spreadsheetgear provides to perform an formula is:
string formula = "{formula from textarea}"
worksheet.EvaluateValue(formula)
and it's expect and string.
As I don't know what formula user will write, or how many parameters this formula has and what are the parameters data type, it's kind difficult to validate.
Now my question is?
How could I validate the expression?
I think in an alternative: Provide to user and page with textbox for each parameter in the expression. The user will be able to provide some data and validate the RESULT of formula. If the sintaxe of formula is wrong the application throw an exception.
It would be a good solution, but for each "PROCESS" that user will interact to, He'll write 10, 15 formulas, and maybe it would be little painful.
Anyone could provide me an Good solution for that?
Thank you!

https://sites.google.com/site/akshatsharma80/home/data-structures/validate-an-arithmetic-expression
refer this site for validation

This is a very late response but I have been working on expression evaluators in Excel with VBA for a while and I might shed some light. I have three solutions to try but all have limitations.
1) Ask the user to put a '$' after a variable name to signify a string (or some other unique character). Drawback is that it is not as simple as typing a single letter for a variable.
2) Assume all variables entered are double precision. Then change the variable to strings in all combinations until one combination works. Could be very time consuming to try all the combinations if the user enters lots of individual variables.
3) Assume all variables entered are double precision. But then have a list in your program of functions that require strings for parameters. Then you could parse the expression, lookup the functions in your list and then designate the parameters that require string input with a string signifier (like in step 1). This will not account for user defined functions.
Now to test out the function, replace all the numeric variables with '1' and all the string variables with "a", then EvaluateValue. If you get a result or an error signifying a calculation error, it is good.
BTW, in order to parse the expression, I suggest the following method. I do not know C#, only VB, so I will only talk in general terms.
1) Take your expression string and do a search and replace of all the typical operators with the same operator but with a backslash ("\") in front and behind the operator (you can use any other character that is not normally used in Excel formulas if you like). This will delineate these operators so that you can easily ignore them and split up your expression into chunks. Typically only need to delineate +,-,/,*,^,<,>,= and {comma}. So search for a "+" and replace it with a "\+\" and so on. For parenthesis, replace "(" and ")" with "(\\" and "\\)" respectively.
So your sample formula "SUM(A, SQRT(B, C)) * PI()" will look like this:
"SUM(\\A\,\ SQRT(\\B\,\ C\\)\\) \*\ PI(\\\\)"
You can also clean up the string a bit more by eliminating any spaces and by eliminating redundant backslashes by replacing every three consecutive backslashes with a single one (replace "\\" with "\").
2) In Visual Basic there is a command called 'Split' that can take a string like this and split it into a one dimensional array using a delimiter (in this case, the backslash). There must be an equivalent in C# or you can just make one. Your array will look like this: "SUM(", "", "A", ",", "SQRT(", "", "B", etc.
Now iterate through your array, starting at the first element and then skipping every other element. These elements will either be a number (a numeric test), a variable, a function (with have a "(" at the end of it), a parenthesis or blank.
Now you can do other checks as you need and replace the variables with actual values.
3) When you are done, rejoin the array back into a string, without any delimiters, and try the Evaluate function.

Writing leading zeros to an Access database

Using C# and SQL I need to write a telephone number to an Access database. The value gets written to the database but the leading zero is lost in the database itself. How can I keep the leading zero?
Thanks in advance.

Use a Text field instead of a numeric one. Numeric fields do not retain formatting information (such as leading zeroes).

Easiest way of working with a comma separated list

I'm about to build a solution to where I receive a comma separated list every night. It's a list with around 14000 rows, and I need to go through the list and select some of the values in the list.
The document I receive is built up with around 50 semicolon separated values for every "case". How the document is structured:
"";"2010-10-17";"";"";"";Period-Last24h";"Problem is that the customer cant find....";
and so on, with 43 more semicolon statements. And every "case" ends with the value "Total 515";
What I need to do is go through all these "cases" and withdraw some of the values in the "cases". The "cases" is always built up in the same order and I know that it's always the 3, 15 and 45'th semicolon value that I need to withdraw.
How can I do this in the easiest way?

I think you should decompose this problem into smaller problems. Here are the steps I'd take:
Each semi-colon separated record represents a single object. C# is an object-oriented language. Stop thinking in terms of .csv records and start thinking in terms of objects. Break up the input into semi-colon delimited records.
Given a single comma-separated record, the values represent the properties of your object. Give them meaningful names.
Parse a comma-separated record into an object. When you're done, you'll have a collection of objects that you can deal with.
Use C#'s collections and LINQ to filter your list based on those cases that you need to withdraw. When you're done, you'll have a collection of objects with the desired cases removed.
Don't worry about the "easiest" way. You need one way that works. Whatever you do, get something working and worry about optimizing it to make it easiest, fastest, smallest, etc. later on.

Assuming the "rows" are lines and that you read line by line, your main tool should be string.Split:
foreach (string line in ... )
{
string [] parts = line.split (';');
string part3 = parts[2];
string part15 = parts[14];
// etc
}
Note that this is a simple approach that will fail if the content of any column can contain ';'

You could use String.Split twice.
The first time using "Total 515"; as the split string using this overload. This will give you an array of cases.
The second time using ";" as the split character using this overload on each of the cases. This will give you a data array for each case. As the data is consistent you can extract the 3rd, 15th and 45th elements of this array.

I'd search for an existing csv library. The escaping rules are probably not that easily mapped to regex.
If writing a library myself I'd first parse each line into a list/an array of strings. And then in a second step(probably outside of the csv library itself) convert the stringlist to a strongly typed object.

A simple but slow approach would be reading single characters from the input (StringReader class, for example). Write a ReadItem method that reads a quote, continues to read until the next quote, and then looks for the next character. If it is a newline of semicolon, one item has been read. If it is another quote, add a single quote to the item being read. Otherwise, throw an exception. Then use this method to split up the input data into a series of items, each line stored e.g. in a string[number of items in a row], lines stored in a List<>. Then you can use this class to read the CSV data inside another class that decodes the data read into objects that you can get your data out of.