I have this function. The visual studio profile marked the line with string.Format as hot and were i spend much of my time.
How can i write this loop more efficiently?
public string EscapeNoPredicate(string sz)
{
var s = new StringBuilder(sz);
s.Replace(sepStr, sepStr + sepStr);
foreach (char v in IllegalChars)
{
string s2 = string.Format("{0}{1:X2}", seperator, (Int16)v);
s.Replace(v.ToString(), s2);
}
return s.ToString();
}
Instead of calculating s2s foreach v each time this method is called; you can store them precalculated. Of course I am assuming IllegalChars and seperator remains same.
In a string.format you can put objects, so (Int16)v is not needed. You can supply "v"
Related
So i have a string text = "" and when i want to increment i use text+= "something", but i need to make a break line because i will write that text a couple times repeated, but when i do text+="\n" it adds the spaces between the "something" texts but after that it adds another space that i dont want.
I would not do it iteratively. So instead of using a loop, you can use joinToString for that, like this:
lines.joinToString(separator = "\n")
val result = string.substringBeforeLast("\n")
This might help!
fun main() {
var string=""
for (line in 0 until 4){
string += "Something"
if (line!=3){
string+="\n"
}
}
print(string)
}
I'm working (actually more like playing) around with the Bit.ly API, and keep getting the error in the title of this question. So I'm going to show you the code and hopefuly someone can help me resolve this. First the client side code.
var x = service.GetClicks(url, service.BitlyLogin, service.BitlyAPIKey);
Console.WriteLine(x);
Console.ReadLine();
And this is the code that's being called
public List<int> GetClicks(string url, string login, string key)
{
List<int> clicks = new List<int>();
url = Uri.EscapeUriString(url);
string reqUri =
String.Format("http://api.bit.ly/v3/clicks?" +
"login={0}&apiKey={1}&shortUrl={2}&format=xml" +
login, key, url);
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(reqUri);
req.Timeout = 10000; // 10 seconds
Stream stm = req.GetResponse().GetResponseStream();
XmlDocument doc = new XmlDocument();
doc.Load(stm);
// error checking for xml
if (doc["response"]["status_code"].InnerText != "200")
throw new WebException(doc["response"]["status_txt"].InnerText);
XmlElement el = doc["response"]["data"]["clicks"];
clicks.Add(int.Parse(el["global_clicks"].InnerText));
clicks.Add(int.Parse(el["user_clicks"].InnerText));
return clicks;
}
As you can see it's very simple code, nothing complicated, and I can see nothing that causes this error. Anyone out there who has worked with(the full error is Index (zero based) must be greater than or equal to zero and less than the size of the argument list.) the Bit.ly API and can lend a hand?
Instead this
string reqUri =
String.Format("http://api.bit.ly/v3/clicks?" +
"login={0}&apiKey={1}&shortUrl={2}&format=xml" + login, key, url);
Use this
string reqUri = String.Format("http://api.bit.ly/v3/clicks?login={0}&apiKey={1}&shortUrl={2}&format=xml", login, key, url);
Notice that I just changed the plus sign with the comma before "login, key, url);" at the end of the String.Format().
I narrowed it down to a place where I was using string.Format to build an array and has less in the string.Format than what was supposed to. I had it go to Index 3 but only filled to Index 2
Not for your specific case, but I ran into this: make sure that, if you have multiple parameters, you send them as an array of objects instead of an IEnumerable:
IEnumerable<object> myArgs = ...;
string toFormat = "{0} xyz {1}";
String.Format(toFormat, myArgs);
// ERROR, since myArgs is one argument whereas the string template requires two
String.Format(toFormat, myArgs.ToArray());
// Valid, as the Format() accepts an array of objects to fill all arguments in the string
In perl you can write
$string =~ tr/[a,e,i,o,u,y]/[A,E,I,O,U,Y]/;
for example.
Is it possible to achieve the same "translation" effects with VB.Net regexes?
Thanks you!
PS: I'm not searching for a way to port this very example, it's more of a curiosity question :)
There is no standard method for this. You can do it by iterating over each character in your input string and using a dictionary to map it to another character (or leave it unchanged if the character is not found in the dictionary). The result can be built using a StringBuilder for performance reasons.
If performance is not an issue then you might be able to use a few replace operations instead:
s = s.Replace("a", "A")
.Replace("e", "E")
...
.Replace("y", "Y");
Here's one way to do this:
public string fakeTR(string theString, char[] org, char[] rep)
{
for(int i=0;i<org.lenght;i++)
{
theString = theString.Replace(org[i], rep[i]);
}
return theString;
}
You would be able to call it with somewhat clunky but shorter:
string v = "Black in South Dakota";
v = fakeTR(v, new char[]{'B','l','a','c','k'}, new char[]{'W','h','i','t','e'});
H/T http://discuss.joelonsoftware.com/default.asp?dotnet.12.306220.6
I have a list:
Dim list As New List(Of String)
with the following items:
290-7-11
1255-7-12
222-7-11
290-7-13
What's an easy and fast way to search if duplicate of "first block" plus "-" plus "second block" is already in the list. Example the item 290-7 appears twice, 290-7-11 and 290-7-13.
I am using .net 2.0
If you only want to know if there are duplicates but don't care what they are...
The easiest way (assuming exactly two dashes).
Boolean hasDuplicatePrefixes = list
.GroupBy(i => i.Substring(0, i.LastIndexOf('-')))
.Any(g => g.Count() > 1)
The fastest way (at least for large sets of strings).
HashSet<String> hashSet = new HashSet<String>();
Boolean hasDuplicatePrefixes = false;
foreach (String item in list)
{
String prefix = item.Substring(0, item.LastIndexOf('-'));
if (hashSet.Contains(prefix))
{
hasDuplicatePrefixes = true;
break;
}
else
{
hashSet.Add(prefix);
}
}
If there are cases with more than two dashes, use the following. This will still fail with a single dash.
String prefix = item.Substring(0, item.IndexOf('-', item.IndexOf('-') + 1));
In .NET 2.0 use Dictionary<TKey, TValue> instead of HashSet<T>.
Dictionary<String, Boolean> dictionary= new Dictionary<String, Boolean>();
Boolean hasDuplicatePrefixes = false;
foreach (String item in list)
{
String prefix = item.Substring(0, item.LastIndexOf('-'));
if (dictionary.ContainsKey(prefix))
{
hasDuplicatePrefixes = true;
break;
}
else
{
dictionary.Add(prefix, true);
}
}
If you don't care about readability and speed, use an array instead of a list, and you are a real fan of regular expressions, you can do the following, too.
Boolean hasDuplicatePrefixes = Regex.IsMatch(
String.Join("#", list), #".*(?:^|#)([0-9]+-[0-9]+-).*#\1");
Do you want to stop user from adding it?
If so, a HashTable with the key as first block-second block could be of use.
If not, LINQ is the way to go.
But, it will have to traverse the list to check.
How big can this list be?
EDIT: I don't know if HashTable has generic version.
You could also use SortedDictionary which can take generic arguments.
If you're list contains only strings, then you can simply make a method that takes the string you want to find along with the list:
Boolean isStringDuplicated(String find, List<String> list)
{
if (list == null)
throw new System.ArgumentNullException("Given list is null.");
int count = 0;
foreach (String s in list)
{
if (s.Contains(find))
count += 1;
if (count == 2)
return true;
}
return false;
}
If you're numbers have a special significance in your program, don't be afraid to use a class to represent them instead of sticking with strings. Then you would have a place to write all the custom functionality you want for said numbers.
I need to replace some 2- and 3-digit numbers with the same number plus 10000. So
Photo.123.aspx
needs to become
Photo.10123.aspx
and also
Photo.12.aspx
needs to become
Photo.10012.aspx
I know that in .NET I can delegate the replacement to a function and just add 10000 to the number, but I'd rather stick to garden-variety RegEx if I can. Any ideas?
James is right that you want to use the Regex.Replace method that takes a MatchEvaluator argument. The match evaluator delegate is where you can take the numeric string you get in the match and convert it into a number that you can add 10,000 to. I used a lambda expression in place of the explicit delegate because its more compact and readable.
using System;
using System.Text.RegularExpressions;
namespace RenameAspxFile
{
sealed class Program
{
private static readonly Regex _aspxFileNameRegex = new Regex(#"(\S+\.)(\d+)(\.aspx)", RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace | RegexOptions.IgnoreCase);
private static readonly string[] _aspxFileNames= {"Photo.123.aspx", "Photo.456.aspx", "BigPhoto.789.aspx"};
static void Main(string[] args)
{
Program program = new Program();
program.Run();
}
void Run()
{
foreach (string aspxFileName in _aspxFileNames)
{
Console.WriteLine("Renamed '{0}' to '{1}'", aspxFileName, AddTenThousandToPhotoNumber(aspxFileName));
}
}
string AddTenThousandToPhotoNumber(string aspxFileName)
{
return _aspxFileNameRegex.Replace(aspxFileName, match => String.Format("{0}{1}{2}", match.Result("$1"), Int32.Parse(match.Result("$2")) + 10000, match.Result("$3")));
}
}
}
I think that using a RegEx for the match, and a function for the replace is most appropriate in this case, you are doing simple math, use something that is designed to do it.....
Is there any reason it has to be VB.NET?
Perl
s(
Photo\. (\d{2,3}) \.aspx
){
"Photo." . ($1 + 10000) . ".aspx"
}xe
Try the following:
"Photo\./d\.aspx" and replace with "Photo.1000$1.aspx"
"Photo\./d/d\.aspx" and replace with "Photo.100$1.aspx"
"Photo\./d/d/d\.aspx" and replace with "Photo.10$1.aspx"
That is the only way I see this happening.
If it's only two or three digit numbers:
(I assume you are using .NET Regex since we are talking about .aspx files)
Check for: Photo\.{\d\d\d}\.aspx
Replace with: Photo.10\1.aspx
Then check against: Photo\.{\d\d}\.aspx
Replace with: Photo.100\1.aspx
James Curran did it little faster than me but well here is what I have for you. Think it's the smallest code you can have with Regex to do what you want.
Regex regex = new Regex(#"(\d\d\d?)", RegexOptions.None);
string result = regex.Replace(#"Photo.123.asp", delegate(Match m)
{
return "Photo.1"
+ m.Groups[1].Captures[0].Value.PadLeft(4, '0')
+ ".aspx";
}
);
did you try just using PadLeft?
This appears to do what you want:
static public string Evaluator(Match match)
{
return "Photo.1"
+ match.Groups[1].Captures[0].Value.PadLeft(4, '0')
+ ".aspx";
}
public void Code(params string[] args)
{
string pattern = #"Photo\.([\d]+)\.aspx";
string test = "Photo.123.aspx";
Regex regex = new Regex(pattern);
string converted = regex.Replace(test, Evaluator)
Console.WriteLine(converted);
}
This will match the right part of the string, but won't tell you if it's two digits or three.
[^\d][\d]{2,3}[^\d]
Still, you could use that to grab the number, convert it to an int, add 10000, and convert that to the string you need.
Found this question since I was trying to do something similar in Vim.
Ill put the solution here.
:s/Photo\.\d\+\.aspx/\=Photo\.submatch(0)+10000\.aspx/g