string-concatenation

I would like to do the following more efficiently: def repeatChar(char:Char, n: Int) = List.fill(n)(char).mkString def repeatString(char:String, n: Int) = List.fill(n)(char).mkString repeatChar('a',3) // res0: String = aaa repeatString("abc",3) // res0: String = abcabcabc Travis Brown For strings you can just write "abc" * 3 , which works via StringOps and uses a StringBuffer behind the scenes. For characters I think your solution is pretty reasonable, although char.toString * n is arguably clearer. Do you have any reason to suspect the List.fill version isn't efficient enough for your needs?

How do I concatenate strings in Entity Framework 4 I have a data from a column and I want to save as a string a comma separated string like "value1, value2, value3" Is there a method or an operator do do this in EF4? Example: lets say that I have two columns Fruit and Farms with the following values: Apples Bananas Strawberries If I do like this var dataSource = this.context .Farms .Select(f => new { f.Id, Fruits = string.Join(", ", f.Fruits) }); Sure I will get this error LINQ to Entities does not recognize the method 'System.String Join(System.String, System.Collections.Generic.IEnumerable`1

As you may know, in JavaScript '' + null = "null" and '' + undefined = "undefined" (in most browsers I can test: Firefox, Chrome and IE). I would like to know the origin of this oddity (what the heck was in the head on Brendan Eich?!) and if there is any aim for changing it in a future version of ECMA. It's indeed pretty frustrating having to do 'sthg' + (var || '') for concatenating Strings with variables and using a third party framework like Underscore or other for that is using a hammer for jelly nail pounding. Edit: To meet the criteria required by StackOverflow and clarify my question,

I have a directory for which I want to list all the .doc files with a ; . I know the following batch command echos all the files: for /r %%i In (*.doc) DO echo %%i But now I want to put them all in a variable, add a ; in between and echo them all at once. How can I do that? set myvar="the list: " for /r %%i In (*.doc) DO <what?> echo %myvar% What about: @echo off set myvar="the list: " for /r %%i in (*.doc) DO call :concat %%i echo %myvar% goto :eof :concat set myvar=%myvar% %1; goto :eof Based on Rubens' solution, you need to enable Delayed Expansion of env variables (type "help setlocal" or

In python say you have s = "string" i = 0 print s+i will give you error so you write print s+str(i) to not get error. I think this is quite a clumsy way to handle int and string concatenation. Even Java does not need explicit casting to String to do this sort of concatenation. Is there a better way to do this sort of concatenation i.e without explicit casting in Python? Modern string formatting: "{} and {}".format("string", 1) No string formatting: >> print 'Foo',0 Foo 0 String formatting, using the new-style .format() method (with the defaults .format() provides): '{}{}'.format(s, i) Or the

I'm trying to understand what the best practice is and why for concatenating string literals and variables for different cases. For instance, if I have code like this StringBuilder sb = new StringBuilder("AAAAAAAAAAAAA") .append(B_String).append("CCCCCCCCCCC").append(D_String) .append("EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE") .append("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"); Is this the way to do it? From this post , I noticed that the + operator on Strings creates a new instance of StringBuilder, concatenates the operands, and returns a String conversion

I have a array that looks like this: $array = [ ["444", "0081"], ["449", "0081"], ["451", "0081"], ["455", "2100"], ["469", "2100"] ]; I need to group as a new array that looks like: array ( 0 => array ( 0 => '444,449,451', 1 => '0081', ), 1 => array ( 0 => '455,469', 1 => '2100', ), ) I'd tried many scripts, but with no success. function _group_by($array, $key) { $return = array(); foreach($array as $val) { $return[$val[$key]][] = $val; } return $return; } $newArray = _group_by($array, 1); // (NO SUCCESS) Giedrius There should be more elegant solutions, but simplest one I can think of would