I have a coded string that I'd like to retrieve a value from. I realize that I can do some string manipulation (IndexOf, LastIndexOf, etc.) to pull out 12_35_55_219 from the below string but I was wondering if there was a cleaner way of doing so.
"AddedProject[12_35_55_219]0"
If you can be sure of the format of the string, then several possibilities exist:
My favorite is to create a very simple tokenizer:
string[] arrParts = yourString.Split( "[]".ToCharArray() );
Since there is a regular format to the string, arrParts will have three entries, and the part you're interested in would be arrParts[1].
If the string format varies, then you will have to use other techniques.
So in summary, if you have a pattern that you can apply to your string, the easiest is to use regular expressions, as per Guffa example.
On the other hand you have different tokens all the time to define the start and end of your string, then you should use the IndexOf and LastIndexOf combination and pass the tokens as a parameter, making the example from Fredrik a bit more generic:
string GetMiddleString(string input, string firsttoken, string lasttoken)
{
int pos1 = input.IndexOf(firsttoken) + 1;
int pos2 = input.IndexOf(lasttoken);
string result = input.Substring(pos1 , pos2 - pos1);
return result
}
And this is assuming that your tokens only happens one time in the string.
That depends on how much the string can vary. You can for example use a regular expression:
string input = "AddedProject[12_35_55_219]0";
string part = Regex.Match(input, #"\[[\d_]+\]").Captures[0].Value;
There are two methods which you may find useful, there is IndexOf and LastIndexOf with the square brackets as your parameters. With a little bit of research, you should be able to pull out the project number.
Here is a improvement from Wagner Silveira's GetMiddleString
string GetMiddleString(string input, string firsttoken, string lasttoken)
{
int pos1 = input.ToLower().IndexOf(firsttoken.ToLower()) + firsttoken.Length;
int pos2 = input.ToLower().IndexOf(lasttoken.ToLower());
return input.Substring(pos1 , pos2 - pos1);
}
And here how you use it
string data = "AddedProject[12_35_55_219]0";
string[] split = data.Split("[]".ToCharArray());
rtbHelp.Text += GetMiddleString(data, split[0], split[2]).Trim("[]".ToCharArray());//print it to my C# winForm RichTextBox Help
Related
I've something like below.
var amount = "$1,000.99";
var formattedamount = string.Format("{0}{1}{0}", "\"", amount);
How can I achieve same using String interpolation?
I tried like below
var formattedamount1 = $"\"{amount}\"";
Is there any better way of doing this using string interpolation?
Update
Is there any better way of doing this using string interpolation
No, this is just string interpolation, you cant make the following any shorter and more readable really
var formattedamount1 = $"\"{amount}\"";
Original answer
$ - string interpolation (C# Reference)
To include a brace, "{" or "}", in the text produced by an
interpolated string, use two braces, "{{" or "}}". For more
information, see Escaping Braces.
Quotes are just escaped as normal
Example
string name = "Horace";
int age = 34;
Console.WriteLine($"He asked, \"Is your name {name}?\", but didn't wait for a reply :-{{");
Console.WriteLine($"{name} is {age} year{(age == 1 ? "" : "s")} old.");
Output
He asked, "Is your name Horace?", but didn't wait for a reply :-{
Horace is 34 years old.
Same thing you can achieve by doing:
var formattedamount1 = $"\"{amount}\"";
OR
var formattedamount1 = $#"""{amount}""";
It's basically allowing you to write string.Format(), but instead of using one string with "placeholders"({0}, {1}, .. {N}), you are directly writing/using your variable inside string.
Please read more about String Interpolation (DotNetPerls), $ - string interpolation to fully understand whats going on.
Just to give one more option, if you want to make sure you use the same quote at both the start and the end, you could use a separate variable for that:
string quote = "\"";
string amount = "$1,000.99";
string formattedAmount = $"{quote}{amount}{quote}";
I'm not sure I'd bother with that personally, but it's another option to consider.
I have a string that I would like to format the same way I would a numeric value.
Ex:
int num = 2;
string option = num.ToString("000");
Console.WriteLine(option);
//output
//002
But the only way I can think to format it is to parse it as an int, then apply the ToString("000") method to it.
string option = "2";
option = int.Parse(option).ToString("000");
Is there a better, more direct way to do this?
No, there is no built-in mechanism to "format" a string as if it were a number. Some options:
Use string functions (Pad, Length, Substring) to determine what characters should be added
Parse to a numeric type and use ToString with numeric formatting strings
Use a reqular expression to extract the digits and generate a new string
There's not one "right" answer. Each has risks and benefits in terms of safety (what if the string does not represent a valid integer?), readability, performance, etc.
Would this suit your requirement?
string x = "2";
string formattedX = x.PadLeft(3, '0');
Console.WriteLine(formattedX); //prints 002
So I have this file with a number that I want to use.
This line is as follows:
TimeAcquired=1433293042
I only want to use the number part, but not the part that explains what it is.
So the output is:
1433293042
I just need the numbers.
Is there any way to do this?
Follow these steps:
read the complete line
split the line at the = character using string.Split()
extract second field of the string array
convert string to integer using int.Parse() or int.TryParse()
There is a very simple way to do this and that is to call Split() on the string and take the last part. Like so if you want to keep it as a string:
var myValue = theLineString.Split('=').Last();
If you need this as an integer:
int myValue = 0;
var numberPart = theLineString.Split('=').Last();
int.TryParse(numberPart, out myValue);
string setting=sr.ReadLine();
int start = setting.IndexOf('=');
setting = setting.Substring(start + 1, setting.Length - start);
A good approach to Extract Numbers Only anywhere they are found would be to:
var MyNumbers = "TimeAcquired=1433293042".Where(x=> char.IsDigit(x)).ToArray();
var NumberString = new String(MyNumbers);
This is good when the FORMAT of the string is not known. For instance you do not know how numbers have been separated from the letters.
you can do it using split() function as given below
string theLineString="your string";
string[] collection=theLineString.Split('=');
so your string gets divided in two parts,
i.e.
1) the part before "="
2) the part after "=".
so thus you can access the part by their index.
if you want to access numeric one then simply do this
string answer=collection[1];
try
string t = "TimeAcquired=1433293042";
t= t.replace("TimeAcquired=",String.empty);
After just parse.
int mrt= int.parse(t);
I have a String I want to get the index of the "id:" i.e the id along with the double quotes.
How I am supposed to do so inside C# string.IndexOf function?
This will get the index of the string you want:
var idx = input.IndexOf("\"id:\"");
if you wanted to pull it out you'd do something like this maybe:
var idx = input.IndexOf("\"id:\"");
var val = input.Substring(idx, len);
where len is either a statically known length or also calculated by another IndexOf statement.
Honestly, this could also be done with a Regex, and if an example were available a Regex may be the right approach because you're presumably trying to get the actual value here and it's presumably JSON you're reading.
" is an escape sequence
If you want to use a double quotation mark in your string, you should use \" instead.
For example;
int index = yourstring.IndexOf("\"id:\"");
Remember, String.IndexOf method gets zero-based index of the first occurrence of the your string.
This is a simple approach: If you know double quote is before the Id then take index of id - 1?
string myString = #"String with ""id:"" in it";
var indexOfId = myString.IndexOf("id:") - 1;
Console.WriteLine(#"Index of ""id:"" is {0}", indexOfId);
Reading between the lines, if this is a JSON string, and you have .NET 4 or higher available, you can ask .NET to deserialize the string for you rather than parsing by hand: see this answer.
Alternatively you might consider Json.NET if you're working very heavily with JSON.
Otherwise, as others note, you need to escape the quotes, so for example:
text.IndexOf("\"id:\"")
text.IndexOf(#"""id:""")
or for overengineered legiblity:
string Quoted(string text)
{
return "\"" + text + "\""; // generates unnecessary garbage
}
text.IndexOf(Quoted("id:"))
I feel kind of dumb posting this when this seems kind of simple and there are tons of questions on strings/characters/regex, but I couldn't find quite what I needed (except in another language: Remove All Text After Certain Point).
I've got the following code:
[Test]
public void stringManipulation()
{
String filename = "testpage.aspx";
String currentFullUrl = "http://localhost:2000/somefolder/myrep/test.aspx?q=qvalue";
String fullUrlWithoutQueryString = currentFullUrl.Replace("?.*", "");
String urlWithoutPageName = fullUrlWithoutQueryString.Remove(fullUrlWithoutQueryString.Length - filename.Length);
String expected = "http://localhost:2000/somefolder/myrep/";
String actual = urlWithoutPageName;
Assert.AreEqual(expected, actual);
}
I tried the solution in the question above (hoping the syntax would be the same!) but nope. I want to first remove the queryString which could be any variable length, then remove the page name, which again could be any length.
How can I get the remove the query string from the full URL such that this test passes?
For string manipulation, if you just want to kill everything after the ?, you can do this
string input = "http://www.somesite.com/somepage.aspx?whatever";
int index = input.IndexOf("?");
if (index >= 0)
input = input.Substring(0, index);
Edit: If everything after the last slash, do something like
string input = "http://www.somesite.com/somepage.aspx?whatever";
int index = input.LastIndexOf("/");
if (index >= 0)
input = input.Substring(0, index); // or index + 1 to keep slash
Alternately, since you're working with a URL, you can do something with it like this code
System.Uri uri = new Uri("http://www.somesite.com/what/test.aspx?hello=1");
string fixedUri = uri.AbsoluteUri.Replace(uri.Query, string.Empty);
To remove everything before the first /
input = input.Substring(input.IndexOf("/"));
To remove everything after the first /
input = input.Substring(0, input.IndexOf("/") + 1);
To remove everything before the last /
input = input.Substring(input.LastIndexOf("/"));
To remove everything after the last /
input = input.Substring(0, input.LastIndexOf("/") + 1);
An even more simpler solution for removing characters after a specified char is to use the String.Remove() method as follows:
To remove everything after the first /
input = input.Remove(input.IndexOf("/") + 1);
To remove everything after the last /
input = input.Remove(input.LastIndexOf("/") + 1);
Here's another simple solution. The following code will return everything before the '|' character:
if (path.Contains('|'))
path = path.Split('|')[0];
In fact, you could have as many separators as you want, but assuming you only have one separation character, here is how you would get everything after the '|':
if (path.Contains('|'))
path = path.Split('|')[1];
(All I changed in the second piece of code was the index of the array.)
The Uri class is generally your best bet for manipulating Urls.
To remove everything before a specific char, use below.
string1 = string1.Substring(string1.IndexOf('$') + 1);
What this does is, takes everything before the $ char and removes it. Now if you want to remove the items after a character, just change the +1 to a -1 and you are set!
But for a URL, I would use the built in .NET class to take of that.
Request.QueryString helps you to get the parameters and values included within the URL
example
string http = "http://dave.com/customers.aspx?customername=dave"
string customername = Request.QueryString["customername"].ToString();
so the customername variable should be equal to dave
regards
I second Hightechrider: there is a specialized Url class already built for you.
I must also point out, however, that the PHP's replaceAll uses regular expressions for search pattern, which you can do in .NET as well - look at the RegEx class.
you can use .NET's built in method to remove the QueryString.
i.e., Request.QueryString.Remove["whatever"];
here whatever in the [ ] is name of the querystring which you want to
remove.
Try this...
I hope this will help.
You can use this extension method to remove query parameters (everything after the ?) in a string
public static string RemoveQueryParameters(this string str)
{
int index = str.IndexOf("?");
return index >= 0 ? str.Substring(0, index) : str;
}