string-interpolation

问题 I am currently translating my grid into LESS, but I can't seem to figure out string interpolation. Here's helper class that is supposed to generate all my columns: .createColumns (@colNumber+1) {} .createColumns (@index) when (@index < @colNumber) { (~".col@{index}") { width: @baseWidth * @index; } .createColumns (@index + 1); } .createColumns (01); Problem is, I get error that says something is wrong with this part (~".col@{index}") . Here's the error message: ParseError: Unrecognised input

问题 I am currently translating my grid into LESS, but I can't seem to figure out string interpolation. Here's helper class that is supposed to generate all my columns: .createColumns (@colNumber+1) {} .createColumns (@index) when (@index < @colNumber) { (~".col@{index}") { width: @baseWidth * @index; } .createColumns (@index + 1); } .createColumns (01); Problem is, I get error that says something is wrong with this part (~".col@{index}") . Here's the error message: ParseError: Unrecognised input

问题 In Scala, while querying Cassandra, this string interpolation s"ALTER TABLE ${keyspace}.\"${tableName}\" " gives me this error: error: value $ is not a member of String [INFO] val query:String=s"ALTER TABLE ${keyspace}.\"${tableName}\" ADD $colName $dataTypeAsString;" What am I doing wrong? 回答1: The \" does not work inside string interpolations. Try using strings delimited by triple quotes: s"""ALTER TABLE ${keyspace}."${tableName}" """ or escape the inner double quotes by additional ${...} :

问题 I often want to copy/paste sql out of my program code and test/debug in psql and it is tedious to have to replace positional arguments with literal values. Is there a good way to convert: select * from users where name=$1 and email=$2; to: select * from users where name='troy' and email='t@me.com'; 回答1: You could use psql variables. Those are interpolated in SQL code. Per documentation: A key feature of psql variables is that you can substitute ("interpolate") them into regular SQL statements

问题 A function in swift takes any numeric type in Swift (Int, Double, Float, UInt, etc). the function converts the number to a string the function signature is as follows : func swiftNumbers <T : NumericType> (number : T) -> String { //body } NumericType is a custom protocol that has been added to numeric types in Swift. inside the body of the function, the number should be converted to a string: I use the following var stringFromNumber = "\(number)" which is not so elegant, PLUS : if the

问题 I have a python logger set up, using python's logging module. I want to store the string I'm using with the logging Formatter object in a configuration file using the ConfigParser module. The format string is stored in a dictionary of settings in a separate file that handles the reading and writing of the config file. The problem I have is that python still tries to format the file and falls over when it reads all the logging-module-specific formatting flags. { "log_level":logging.debug, "log

问题 Why does string interpolation prefer overload of method with string instead of IFormattable ? Imagine following: static class Log { static void Debug(string message); static void Debug(IFormattable message); static bool IsDebugEnabled { get; } } I have objects with very expensive ToString() . Previously, I did following: if (Log.IsDebugEnabled) Log.Debug(string.Format("Message {0}", expensiveObject)); Now, I wanted to have the IsDebugEnabled logic inside Debug(IFormattable) , and call

问题 My question is about how to convert array elements to string in ruby 1.9 without getting the brackets and quotation marks. I've got an array (DB extract), from which I want to use to create a periodic report. myArray = ["Apple", "Pear", "Banana", "2", "15", "12"] In ruby 1.8 I had the following line reportStr = "In the first quarter we sold " + myArray[3].to_s + " " + myArray[0].to_s + "(s)." puts reportStr Which produced the (wanted) output In the first quarter we sold 2 Apple(s). The same

问题 Why does string interpolation in c# does not work with const strings? For example: private const string WEB_API_ROOT = "/private/WebApi/"; private const string WEB_API_PROJECT = $"{WEB_API_ROOT}project.json"; From my point of view, everything is known at compile time. Or is that a feature that will be added later? Compiler message: The expression being assigned to 'DynamicWebApiBuilder.WEB_API_PROJECT' must be constant. Thanks a lot! 回答1: Interpolated strings are simply converted to calls to

问题 Does the Kotlin compiler translate "Hello, $name!" using something like java.lang.String.format("Hello, %s!", name) or is there some other mechanism? And if I have a class like this for example: class Client { val firstName: String val lastName: String val fullName: String get() = "$firstName $lastName" } Will this getter return a cached string or will it try to build a new string? Should I use lazyOf delegate instead? I know that there will be no performance issue unless there will be