Develop Reference

How to slice/trim this value?

I am trying to remove the last 6 characters from item.Size because the data has a decimal place and 5 trailing 0s in the database.
sb.Append("<div>" + item.Size + " " + item.Units + " </div>");
ie. item.Size is displayed as 1.00000 and I need it to just be displayed as 1.
This is part of a StringBuilder, and as I'm new to coding, not even sure the right way to go about this.

sb.Append("<div>" + (int)item.Size + " " + item.Units + " </div>");

StringBuilder has the same formatting capabilities as String.Format when you use the AppendFormat method:
sb.AppendFormat("<div>{0:N0} {1} </div>", item.Size, item.Units);
The format string "N0" tells it to format the number with 0 decimal points. That assumes the item.Size is stored as a numerical type. If not, simply remove the part of the string you don't want:
sb.AppendFormat("<div>{0} {1}</div>", item.Size.Split('.')[0], item.Units);
Here I've used Split, assuming that the value is actually something like what you've shown in your example.

Better you use int.TryParse(or Int32.TryParse) method. because if item.Size is not convertible to int, then it wont give you any exception. you can use int or long according to your choice. So you can handle this in your code according to the if/else condition.
Sample Code:
int size;
string str = "";
if(int.TryParse(str, out size) == true)
{
}
else
{
}

How can I add a SPACE halfway through a string value?

I'm trying to create a STRING in JSON format. However, one of the fields (from my editing/removing ALL spaces) now leaves a line like "START":"13/08/1410:30:00". However, I want to add a space between the date and time? I have tried using the ToCharArray() method to split the string, but I am at a loss as to how to add a space between the DATE and TIME part of the string?
For Example, i am trying to get: "START":"13/08/14 10:30:00" but instead am getting
"START":"13/08/1410:30:00"
Please note. The length of the string before the space requirement will always be 17 characters long. I am using VS 2010 for NETMF (Fez Panda II)

If the split position is always 17, then simply:
string t = s.Substring(0, 17) + " " + s.Substring(17);

Obviously you will have to sort the numbers out, but thats the general idea.
String.Format("{0} {1}", dateString.Substring(0, 17), dateString.Substring(17, dateString.Length - 17);
Or you can use the StringBuilder class:
var finalString = new StringBuilder();
for (var i = 0; i < dateString.Length; i++){
if (i == 17)
finalString.Add(" ");
else
finalString.Add(dateString.ToCharArray()[i]);
}
return finalString.ToString();

If the date time format always the same you can use string.Insert method
var output = #"""START"":""13/08/1410:30:00""".Insert(17, " ");

Strings in .Net are immutable: you can never change them. However, you can easily create a new string.
var date_time = dateString + " " + timeString;

Numeric fields lose leading zero while writing CSV in c#

I'm using an ASP.NET application which exports my clients data to CSV, I need my clients Phone number to be with the leading Zero.
I need the phone numbers to be without "-" and without quotations, and due to the nature of my application I cannot use 3rd party products such as EPPLUS.
I've tried to put a space and let the CSV "understand" that I need the phone number as text , but that doesn't seem right.
I would like to know how to make the excel include the leading zero , without using 3rd party products.
Thanks

Change the data that is saved in the csv with the following format:
="00023423"
CSV example:
David,Sooo,="00023423",World
This will show 00023423 in excel and not 23423.

public void CreatingCsvFiles(Client client)
{
string filePath = "Your path of the location" + "filename.csv";
if (!File.Exists(filePath))
{
File.Create(filePath).Close();
}
string delimiter = ",";
string[][] output = new string[][]{
new string[]{ "=\"" + client.phone + "\"", client.name }
};
int length = output.GetLength(0);
StringBuilder sb = new StringBuilder();
for (int index = 0; index < length; index++)
sb.AppendLine(string.Join(delimiter, output[index]));
File.AppendAllText(filePath, sb.ToString());
}
Inspired from http://softwaretipz.com/c-sharp-code-to-create-a-csv-file-and-write-data-into-it/
The important part :
"=\"" + client.phone + "\"", client.name
If the phone number is an int, of course you add .toString().

Print phone number to CSV with prepended ' (single quote), so it looks like:
"Some Name","'0000121212"
Excel should treat this 0000121212 as string then.

I believe converting the number into a formula like the accepted answer might not be a helpful solution for all.
The alternate solution I went with is to just add a tab space before the integer value.
Example:
Taking phoneNumber as a string variable which contains our int value
Solution:
"\t" + phoneNumber

If you know already how much numbers has to be inside phone you can do like this
phoneNumber.ToString("000000000000")
In this example I consider that phoneNumber is an int and required length of numbers is 12.

C# , Substring How to access last elements of an array/string using substring

I am generating 35 strings which have the names ar15220110910, khwm20110910 and so on.
The string contains the name of the Id (ar152,KHWM), and the date (20110910). I want to extract the Id, date from the string and store it in a textfile called StatSummary.
My code statement is something like this
for( int 1= 0;i< filestoextract.count;1++)
{
// The filestoextract contains 35 strings
string extractname = filestoextract(i).ToString();
statSummary.writeline( extractname.substring(0,5) + "" +
extractname.substring(5,4) + "" + extractname.substring(9,2) + "" +
extractname.substring(11,2));
}
When the station has Id containing 5 letters, then this code executes correctly but when the station Id is KHWM or any other 4 letter name then the insertion is all messed up. I am running this inside a loop. So I have tried keeping the code as dynamic as possible. Could anyone help me to find a way without hardcoding it. For instance accessing the last 8 elements to get the date??? I have searched but am not able to find a way to do that.

For the last 8 digits, it's just:
extractname.Substring(extractname.Length-8)
oh, I'm sorry, and so for your code could be:
int l = extractname.Length;
statSummary.WriteLine(extractname.substring(0,l-8) + "" +
extractname.Substring(l-8,4) + "" + extractname.Substring(l-4,2) + "" +
extractname.Substring(l-2,2));

As your ID length isn't consistent, it would probably be a better option to extract the date (which is always going to be 8 chars) and then treat the remainder as your ID e.g.
UPDATED - more robust by actually calculating the length of the date based on the format. Also validates against the format to make sure you have parsed the data correctly.
var dateFormat = "yyyyMMdd"; // this could be pulled from app.config or some other config source
foreach (var file in filestoextract)
{
var dateStr = file.Substring(file.Length-dateFormat.Length);
if (ValidateDate(dateStr, dateFormat))
{
var id = file.Substring(0, file.Length - (dateFormat.Length+1));
// do something with data
}
else
{
// handle invalid filename
}
}
public bool ValidateDate(stirng date, string date_format)
{
try
{
DateTime.ParseExact(date, date_format, DateTimeFormatInfo.InvariantInfo);
}
catch
{
return false;
}
return true;
}

You could use a Regex :
match = Regex.Match ("khwm20110910","(?<code>.*)(?<date>.{6})" );
Console.WriteLine (match.Groups["code"] );
Console.WriteLine (match.Groups["date"] );
To explain the regex pattern (?<code>.*)(?<date>.{6}) the brackets groups creates a group for each pattern. ?<code> names the group so you can reference it easily.
The date group takes the last six characters of the string. . says take any character and {6} says do that six times.
The code group takes all the remaining characters. * says take as many characters as possible.

for each(string part in stringList)
{
int length = part.Length;
int start = length - 8;
string dateString = part.Substring(start, 8);
}
That should solve the variable length to get the date. The rest of the pull is most likely dependent on a pattern (suggested) or the length of string (when x then the call is 4 in length, etc)

If you ID isn't always the same amount of letters you should seperate the ID and the Date using ',' or somthing then you use this:
for( int 1= 0;i< filestoextract.count;1++)
{
string extractname = filestoextract[i].ToString();
string ID = extractname.substring(0, extractname.IndexOf(','));
string Date = extractname.substring(extractname.IndexOf(','));
Console.WriteLine(ID + Date);
}

How does the C# compiler work with a split?

I have an List<string> that I am iterating through and splitting on each item then adding it to a StringBuilder.
foreach(string part in List)
{
StringBuilder.Append(part.Split(':')[1] + " ");
}
So my question is how many strings are created by doing this split? All of the splits are going to produce two items. So... I was thinking that it will create a string[2] and then an empty string. But, does it then create the concatenation of the string[1] + " " and then add it to the StringBuilder or is this optimized?

The code is actually equivalent to this:
foreach(string part in myList)
{
sb.Append(string.Concat(part.Split(':')[1], " "));
}
So yes, an additional string, representing the concatenation of the second part of the split and the empty string will be created.
Including the original string, you also have the two created by the call to Split(), and a reference to the literal string " ", which will be loaded from the assembly metadata.
You can save yourself the call to Concat() by just Appending the split result and the empty string sequentially:
sb.Append(part.Split(':')[1]).Append(" ");
Note that if you are only using string literals, then the compiler will make one optimzation for you:
sb.Append("This is " + "one string");
is actually compiled to
sb.Append("This is one string");

3 extra strings for every item
part[0];
part[1];
part[1] + " "
the least allocations possible would be to avoid all the temporary allocations completely, but the usual micro-optimization caveats apply.
var start = part.IndexOf(':') + 1;
stringbuilder.Append(part, start, part.Length-start).Append(' ');

You have the original string 'split' - 1 string
You have the 'split' split into two - 2 string
You have the two parts of split joined - 1 string
The string builder does not create a new string.
The current code uses 4 strings, including the original.
If you want to save one string do:
StringBuilder.Append(part.Split(':')[1]);
StringBuilder.Append(" ");

This code:
foreach(string part in List)
{
StringBuilder.Append(part.Split(':')[1] + " ");
}
Is equivalent to:
foreach(string part in List)
{
string tmp = string.Concat(part.Split(':')[1], " ");
StringBuilder.Append(tmp);
}
So yes, it's creating a string needlessly. This would be better, at least in terms of the number of strings generated:
foreach(string part in List)
{
StringBuilder.Append(part.Split(':')[1])
.Append(" ");
}

So for each value in the list (n, known as part in your code) you are allocating:
x (I assume 2) strings for the split.
n strings for the concatenation.
Roughly n + 1 string for the StringBuilder; probably much less though.
So you have nx + n + n + 1 at the end, and assuming the split always results in two values 4n + 1.
One way to improve this would be:
foreach(string part in List)
{
var val = part.Split(':')[1];
StringBuilder.EnsureCapacity(StringBuilder.Length + val.Length + 1);
StringBuilder.Append(val);
StringBuilder.Append(' ');
}
This makes it 3n + 1. It is a rough estimate as StringBuilder allocates strings as it runs out of space - but if you EnsureCapacity you will prevent it from getting it wrong.

Probably the only way to be sure about how this is compiled is to build it and decompile it again with Refactor to see how it's internally handled. Anyway have in mind that probably it does not have impact on the whole app performance.