Why Wont This Code Snip Something From A String - c#

So I have data which has data separated by ", ". I am trying to separate the different data using Substring.
input = input.Substring(input.IndexOf(", ") + 2, input.Length - input.IndexOf(", ") + 2);
In this scenario, I have already read the first piece of data and I am trying to cut it off. In order to do this, I take the index of the first instance of ", " and add 2 to it, which gives me the end index of the phrase. Then I take the length of the entire string and subtract the last index of the first ", ". This gives me the length from the end of ", " to the end of the string. This is what I want to snip. For some reason, I keep getting an ArgumentOutOfRange exception when this piece of code runs. If someone could tell me what I am doing wrong, it would be very helpful.

Then I take the length of the entire string and subtract the last
index of the first ", ".
Not so - you forgot parenthesis around input.IndexOf(", ") + 2. Your intention was to do this:
input = input.Substring(
input.IndexOf(", ") + 2,
input.Length - (input.IndexOf(", ") + 2)); // < note additional "()"
If you were not trying to put everything into one line - you could have avoided this problem:
var idx = input.IndexOf(", ") + 2;
input = input.Substring(idx, input.Length - idx);
You can also use Remove to achieve the same result:
input = input.Remove(0, input.IndexOf(", ") + 2);

Related

String randomly containing a newline C#

I'm completely lost with what is happening here.
string send = "!points add " + entries[winner] + " " + prize.ToString();
What I want to send is "!points add winnername prizeamount" but what I get is "!points add winnername\nprizeamount". I put \n because it writes a new line but trying to replace "\n", "\r" and "\t" with " " does nothing.
enter image description here
all I need is the message to be exactly"!points space add space winnername space prizeamount space"
If it's important the entries in my code is a List of strings
The entries strings already contain the new line character(s).
I suggest you replace with Environment.NewLine:
Replace Line Breaks in a String C#
The string object, 'entries[winner]' is having line-feeds (LF) or carriage-returns (CR). You try this to remove all LFs and CRs,
string send = "!points add "
+ entries[winner].Replace("\r", string.Empty).Replace("\n", string.Empty)
+ " " + prize.ToString();
Alternatively, you can use Trim() to remove leading\ trailing LFs\ CRs.
string send = "!points add "
+ entries[winner].Trim()
+ " " + prize.ToString();
No repro. The following code doesn't assert.
var entries=new List<string>{"Aaa", "Bbb", "Ccc"};
int prize=90;
int winner=1;
var send=String.Format("!points add {0} {1}",entries[winner],prize);
var send2="!points add " + entries[winner] + " " + prize.ToString();
Trace.Assert("!points add Aaa 90"==send);
Trace.Assert(send2==send);
If the result contains newlines, it's because the entries values contain newlines.
The best solution would be to clean the input data before storing it in the list, eg with String.TrimEnd or String.Trim, When loading data from a file for example, you can't be sure it doesn't contain trailing spaces.
To read clean data from a file you could use :
var entries=File.ReadLines()
.Select(line=>line.Trim())
.ToList();
If you add the entries one by one from user input :
entries.Add(newEntry.Trim());
If you can't change how the data is read (why?) you can trim when whenever you use an entry value:
var send=String.Format("!points add {0} {1}",entries[winner].Trim(),prize);
Loading clean data is a lot easier

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
{
}

Get a specific word from a line read from a .txt

right now I am reading some lines from a .txt.
Lets say, a user enters his name and in the .txt will be saved "Logged in {username} on 13/04/2016 at 10:55 am".
(Just an example.)
Now I want to read the .txt and print only specific parts into a textbox.
Meaning, in the textbox shall appear "{Username} - 13/04/2016 - 10:55 am".
So far, I am able to read from the .txt and print the whole line.
private void button_print_results_Click(object sender, RoutedEventArgs e)
{
int counter = 0;
string actual_line;
System.IO.StreamReader file_to_read =
new System.IO.StreamReader("myText.txt");
while ((actual_line = file_to_read.ReadLine()) != null)
{
textBox_results.Text = textBox_results.Text +"\n"+ actual_line;
counter++;
}
file_to_read.Close();
}
Is there a way, to reach this without overwriting the whole file?
And no, I can't change the format how the names etc. are saved.
(I used them here for a better understanding, the actual lines I need to read/check are different and auto-generated).
I don't expect full working code, it would be just great if you could tell me for which commands I need to look. Been a long time since I last worked with c#/wpf and I never worked much with Streamreader...
Thanks
I think regular expressions is the best tool for what you're trying to achieve. You can write something like this:
Regex regex = new Regex("Logged in (?<userName>.+) on (?<loginTime>.+)");
while ((actual_line = file_to_read.ReadLine()) != null)
{
Match match = regex.Match(actual_line);
if (match.Success) {
string loginInfo = string.Format("{0} - {1}", match.Groups["userName"], match.Groups["loginTime"]);
textBox_results.Text = textBox_results.Text +"\n"+ loginInfo;
}
}
There are couple of possible solutions for this. One most straight forward way for your case would be to use Substring and Replace.
Since the earlier string is always Logged in (note the last space) and you simply want to get the rests of the string after the phrase, replacing only the preposition of time words (" on ", " at ") with dash (" - ") you could take advantage on that:
string str = "Logged in {username} on 13/04/2016 at 10:55 am";
string substr = str.Substring(("Logged in ").Length) //note the last space
.Replace(" on ", " - ")
.Replace(" at ", " - ");
In your implementation, this is how it look like:
while ((actual_line = file_to_read.ReadLine()) != null)
{
actual_line = actual_line.Substring(("Logged in ").Length) //note the last space
.Replace(" on ", " - ")
.Replace(" at ", " - ");
textBox_results.Text = textBox_results.Text +"\n"+ actual_line;
counter++;
}
(Note: the solution above assumes the {username} does not contain spaced preposition of time words - which would almost likely be the case for a {username})
You could split the actual_line String so you get an array of Strings. And then fill the Strings you want to show in the TextBox into it.
string[] values = actual_line.Split(' ');
textBox_results.Text = textBox_results.Text + "\n" + values[2] + " " + values[6] + " " + values[7];
The text in the TextBox for example is "{username} 10:55 am"
You can use Regex for better performances as #Dmitry-Rotay suggested in the previous comment, but if you jave a not-so-big file your loop+string manipulations is an acceptable compromise.
Always use Environment.NewLine instead of "\n", it's more portable.
while ((actual_line = file_to_read.ReadLine()) != null)
{
actual_line = actual_line
.Replace(("Logged in "), String.Empty)
.Replace(" on ", " - ")
.Replace(" at ", " - ");
textBox_results.Text = textBox_results.Text
+ System.Environment.NewLine
+ actual_line;
counter++;
}

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;

c# richtextbox only shows one line

been searching the internet for some time now and cant find a solution to my problem.
I'm trying to parse some lines into the richtextbox, but i only get one line instead of all of them. Heres a part of my code
foreach (var val in lineCountDict)
{
richTextBox2.Text = (val.Key + " - " + val.Value + " Drops -" +
((double)val.Value / (double)mobDeathCounter) * 100 + " % chance\n");
}
So when i run this i only get one line, any advice would be awesome
Thank you!
Of course you get one line since in each iteration you set richTextBox2.Text to the new value which replaces the old value.
Use richTextBox2.Text+="..."

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