string-concatenation

In Java, it's a common best practice to do string concatenation with StringBuilder due to the poor performance of appending strings using the + operator. Is the same practice recommended for Scala or has the language improved on how java performs its string concatenation? Scala uses Java strings ( java.lang.String ), so its string concatenation is the same as Java's: the same thing is taking place in both. (The runtime is the same, after all.) There is a special StringBuilder class in Scala, that "provides an API compatible with java.lang.StringBuilder "; see http://www.scala-lang.org/api/2.7

The following statements, String string = "string"; string = string +((char)65) + 5; System.out.println(string); Produce the output stringA5 . The following however, String string = "string"; string += ((char)65) + 5; System.out.println(string); Produce string70 . Where is the difference? Kai Sternad You see this behavior as a result of the combination of operator precedence and string conversion. JLS 15.18.1 states: If only one operand expression is of type String, then string conversion (§5.1.11) is performed on the other operand to produce a string at run time. Therefore the right hand

Is this safe to use require("path").join to concatenate URLs, for example: require("path").join("http://example.com", "ok"); //returns 'http://example.com/ok' require("path").join("http://example.com/", "ok"); //returns 'http://example.com/ok' If not, what way would you suggest for doing this without writing code full of ifs? Matthew Bakaitis No. path.join() will return incorrect values when used with URLs. It sounds like you want url.resolve . From the Node docs : url.resolve('/one/two/three', 'four') // '/one/two/four' url.resolve('http://example.com/', '/one') // 'http://example.com/one'

I want append to a string so that every time I loop over it will add say "test" to the string. Like in PHP you would do: $teststr = "test1\n" $teststr .= "test2\n" echo = "$teststr" echos: test1 test2 But I need to do this in a shell script William Pursell In classic sh, you have to do something like: s=test1 s="${s}test2" (there are lots of variations on that theme, like s="$s""test2" ) In bash, you can use +=: s=test1 s+=test2 $ string="test" $ string="${string}test2" $ echo $string testtest2 #!/bin/bash message="some text" message="$message add some more" echo $message some text add some

What is the best (idiomatic) way to concatenate Strings in Groovy? Option 1: calculateAccountNumber(bank, branch, checkDigit, account) { bank + branch + checkDigit + account } Option 2: calculateAccountNumber(bank, branch, checkDigit, account) { "$bank$branch$checkDigit$account" } I've founded an interesting point about this topic in the old Groovy website: Things you can do but better leave undone. As in Java, you can concatenate Strings with the "+" symbol. But Java only needs that one of the two items of a "+" expression to be a String, no matter if it's in the first place or in the last

Is there a way in SQL sever that can write the output as follow: select events from mytable original output events -------- 123456 894531 985233 829292 920202 392939 299223 desired output '123456', '894531','985233','829292','920202','392939','299223' select '' + CustomerID + ',' from dbo.Customers customerid ALFKI, ANATR, ANTON, AROUT, BERGS, Would like to see the result as customerid 'ALFKI', 'ANATR', 'ANTON', 'AROUT', 'BERGS', so on... SELECT STUFF( (SELECT ', ' + events FROM dbo.mytable FOR XML PATH('') ), 1, 1, '') As concatenated_string If you want the values enclosed in single quotes