When I need to print "00000", I can use "0"*5 in python. Is there equivalent in C# without looping?
Based on your example I figure you're going to be using these strings to help zero-pad some numbers. If that's the case, it would be easier to use the String.PadLeft() method to do your padding. You could be using the similar function in python as well, rjust().
e.g.,
var str = "5";
var padded = str.PadLeft(8, '0'); // pad the string to 8 characters, filling in '0's
// padded = "00000005"
Otherwise if you need a repeated sequence of strings, you'd want to use the String.Concat() method in conjunction with the Enumerable.Repeat() method. Using the string constructor only allows repetition of a single character.
e.g.,
var chr = '0';
var repeatedChr = new String(chr, 8);
// repeatedChr = "00000000";
var str = "ha";
// var repeatedStr = new String(str, 5); // error, no equivalent
var repeated = String.Concat(Enumerable.Repeat(str, 5));
// repeated = "hahahahaha"
One of the String ctor overloads will do this for you:
string zeros = new String('0', 5);
To add to the other answers, you won't be able to use this string constructor with another string to repeat strings, such as string s = new string("O", 5);. This only works with chars.
However, you can use Enumerable.Repeat() after adding using System.Linq; to achieve the desired result with strings.
string s = string.Concat(Enumerable.Repeat("O", 5));
Use
string s = new string( '0', 5 );
Found here
Depending on your application, this may be useful too:
int n = 0;
string s = n.ToString().PadRight(5, '0');
Don't ever, ever use this: string.Join("0", new string[6]);
Why not just "00000" ?! ducks
This one only works with zero: 0.ToString("D5");
Related
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've been using C# String.Format for formatting numbers before like this (in this example I simply want to insert a space):
String.Format("{0:### ###}", 123456);
output:
"123 456"
In this particular case, the number is a string. My first thought was to simply parse it to a number, but it makes no sense in the context, and there must be a prettier way.
Following does not work, as ## looks for numbers
String.Format("{0:### ###}", "123456");
output:
"123456"
What is the string equivalent to # when formatting? The awesomeness of String.Format is still fairly new to me.
You have to parse the string to a number first.
int number = int.Parse("123456");
String.Format("{0:### ###}", number);
of course you could also use string methods but that's not as reliable and less safe:
string strNumber = "123456";
String.Format("{0} {1}", strNumber.Remove(3), strNumber.Substring(3));
As Heinzi pointed out, you can not have format specifier for string arguments.
So, instead of String.Format, you may use following:
string myNum="123456";
myNum=myNum.Insert(3," ");
Not very beautiful, and the extra work might outweigh the gains, but if the input is a string on that format, you could do:
var str = "123456";
var result = String.Format("{0} {1}", str.Substring(0,3), str.Substring(3));
string is not a IFormattable
Console.WriteLine("123456" is IFormattable); // False
Console.WriteLine(21321 is IFormattable); // True
No point to supply a format if the argument is not IFormattable only way is to convert your string to int or long
We're doing string manipulation, so we could always use a regex.
Adapted slightly from here:
class MyClass
{
static void Main(string[] args)
{
string sInput, sRegex;
// The string to search.
sInput = "123456789";
// The regular expression.
sRegex = "[0-9][0-9][0-9]";
Regex r = new Regex(sRegex);
MyClass c = new MyClass();
// Assign the replace method to the MatchEvaluator delegate.
MatchEvaluator myEvaluator = new MatchEvaluator(c.ReplaceNums);
// Replace matched characters using the delegate method.
sInput = r.Replace(sInput, myEvaluator);
// Write out the modified string.
Console.WriteLine(sInput);
}
public string ReplaceNums(Match m)
// Replace each Regex match with match + " "
{
return m.ToString()+" ";
}
}
How's that?
It's been ages since I used C# and I can't test, but this may work as a one-liner which may be "neater" if you only need it once:
sInput = Regex("[0-9][0-9][0-9]").Replace(sInput,MatchEvaluator(Match m => m.ToString()+" "));
There is no way to do what you want unless you parse the string first.
Based on your comments, you only really need a simple formatting so you are better off just implementing a small helper method and thats it. (IMHO it's not really a good idea to parse the string if it isn't logically a number; you can't really be sure that in the future the input string might not be a number at all.
I'd go for something similar to:
public static string Group(this string s, int groupSize = 3, char groupSeparator = ' ')
{
var formattedIdentifierBuilder = new StringBuilder();
for (int i = 0; i < s.Length; i++)
{
if (i != 0 && (s.Length - i) % groupSize == 0)
{
formattedIdentifierBuilder.Append(groupSeparator);
}
formattedIdentifierBuilder.Append(s[i]);
}
return formattedIdentifierBuilder.ToString();
}
EDIT: Generalized to generic grouping size and group separator.
The problem is that # is a Digit placeholder and it is specific to numeric formatting only. Hence, you can't use this on strings.
Either parse the string to a numeric, so the formatting rules apply, or use other methods to split the string in two.
string.Format("{0:### ###}", int.Parse("123456"));
So what I am trying to do is as follows :
example of a string is A4PC
I am trying to replace for example any occurance of "A" with "[A4]" so I would get and similar any occurance of "4" with "[A4]"
"[A4][A4]PC"
I tried doing a normal Replace on the string but found out I got
"[A[A4]]PC"
string badWordAllVariants =
restriction.Value.Replace("A", "[A4]").Replace("4", "[A4]")
since I have two A's in a row causing an issue.
So I was thinking it would be better rather than the replace on the string I need to do it on a character per character basis and then build up a string again.
Is there anyway in Linq or so to do something like this ?
You don't need any LINQ here - String.Replace works just fine:
string input = "AAPC";
string result = input.Replace("A", "[A4]"); // "[A4][A4]PC"
UPDATE: For your updated requirements I suggest to use regular expression replace
string input = "A4PC";
var result = Regex.Replace(input, "A|4", "[A4]"); // "[A4][A4]PC"
This works well for me:
string x = "AAPC";
string replace = x.Replace("A", "[A4]");
EDIT:
Based on the updated question, the issue is the second replacement. In order to replace multiple strings you will want to do this sequentially:
var original = "AAPC";
// add arbitrary room to allow for more new characters
StringBuilder resultString = new StringBuilder(original.Length + 10);
foreach (char currentChar in original.ToCharArray())
{
if (currentChar == 'A') resultString.Append("[A4]");
else if (currentChar == '4') resultString.Append("[A4]");
else resultString.Append(currentChar);
}
string result = resultString.ToString();
You can run this routine with any replacements you want to make (in this case the letters 'A' and '4' and it should work. If you would want to replace strings the code would be similar in structure but you would need to "look ahead" and probably use a for loop. Hopefully this helps!
By the way - you want to use a string builder here and not strings because strings are static which means space gets allocated every time you loop. (Not good!)
I think this should do the trick
string str = "AA4PC";
string result = Regex.Replace(str, #"(?<Before>[^A4]?)(?<Value>A|4)(?<After>[^A4]?)", (m) =>
{
string before = m.Groups["Before"].Value;
string after = m.Groups["After"].Value;
string value = m.Groups["Value"].Value;
if (before != "[" || after != "]")
{
return "[A4]";
}
return m.ToString();
});
It is going to replace A and 4 that hasn't been replaced yet for [A4].
I know this question would have been asked infinite number of times, but I'm kinda stuck.
I have a string something like
"Doc1;Doc2;Doc3;12"
it can be something like
"Doc1;Doc2;Doc3;Doc4;Doc5;56"
Its like few pieces of strings separated by semicolon, followed by a number or id.
I need to extract the number/id and the strings separately.
To be exact, I can have 2 strings: one having "Doc1;Doc2;Doc3" or "Doc1;Doc2;Doc3;Doc4" and the other having just the number/id as "12" or "34" or "45" etc.
And yeah I am using C# 3.5
I understand its a pretty easy and witty question, but this guy is stuck.
Assistance required from experts.
Regards
Anurag
string.LastIndexOf and string.Substring are the keys to what you're trying to do.
var str = "Doc1;Doc2;Doc3;12";
var ind = str.LastIndexOf(';');
var str1 = str.Substring(0, ind);
var str2 = str.Substring(ind+1);
One way:
string[] tokens = str.Split(';');
var docs = tokens.Where(s => s.StartsWith("Doc", StringComparison.OrdinalIgnoreCase));
var numbers = tokens.Where(s => s.All(Char.IsDigit));
String docs = s.Substring(0, s.LastIndexOf(';'));
String number = s.Substring(s.LastIndexOf(';') + 1);
One possible approach would be this:
var ids = new List<string>();
var nums = new List<string>();
foreach (var s in input.Split(';'))
{
int val;
if (!int.TryParse(s, out val)) { ids.Add(s); }
else { nums.Add(s); }
}
where input is something like Doc1;Doc2;Doc3;Doc4;Doc5;56. Now, ids will house all of the Doc1 like values and nums will house all of the 56 like values.
you can use StringTokenizer functionality.
http://www.c-sharpcorner.com/UploadFile/pseabury/JavaLikeStringTokenizer11232005015829AM/JavaLikeStringTokenizer.aspx
split string using ";"
StringTokenizer st = new StringTokenizer(src1,";");
collect final String. that will be your ID.
You may try one of two options: (assuming your input string is in string str;
Approach 1
Get LastIndexOf(';')
Split the string based on the index. This will give you string and int part.
Split the string part and process it
Process the int part
Approach 2
Split the string on ;
Run a for loop - for (int i = 0; i < str.length - 2; i++) - this is the string part
Process str[length - 1] separately - this is the int part
Please take this as a starting point as there could be other approaches to implement a solution for this
string actual = "Doc1;Doc2;Doc3;12";
int lstindex = actual.LastIndexOf(';');
string strvalue = actual.Substring(0, lstindex);
string id = actual.Substring(lstindex + 1);
I am taking numerical input from a text box. I want to check
if(textBox1.Text.Contains("."))
like 55.37
then split the string in two parts/strings.
First part before period (55)
Second part after the period (37)
Use this:
string[] ret = textBox1.Text.Split('.');
Then you can do
if (ret.Length != 2) // error ?!?
ret[0] is integer part
ret[1] is fractional part
var splitted = textBox1.Text.Split('.');
The result will be an array of strings. In your sample, the array will have 2 strings, 55 and 37.
use string.Split method
string[] a = textBox1.Text.Split('.');
string b = a[0];
string c = a[1];
In case there is a chance your code will be executed on OS with non-windows localization please use:
var separators = new[] {CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator};
var parts = textBox1.Text.Split(separators, StringSplitOptions.None);
It looks too verbose but it may be hard to understand why your code works on your machine (with dev environment) but don't on customers.
if (!textBox1.Text.Contains('.'))
return;
var parts = textBox1.Text.Split('.')
should do the trick.
use Split method
dim s as string = textbox1.text
s.split(".")
Use the following:
textBox1.Text.Split('.')