# Strings In CFML, strings are a type of variable that is used to store collections of letters and numbers. Usually defined within single or double quotes ( `'` or `"` ). Some simple strings would be `"hello"` or `"This sentence is a string!"`. Strings can be anything from `""`, the empty string, to long sets of text. The underlying type for a string in CFML is the Java [String](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/String.html), which is immutable, meaning it can never change. Thus, a new string object is always created when concatenating strings together. This is a warning that if you do many string concatenations, you will have to use a Java data type to accelerate the concatenations ([String Builders](https://www.baeldung.com/java-string-builder-string-buffer)). {% hint style="info" %} More on String Builders: {% endhint %} ## Character Extractions In Adobe 2021+ and Lucee server, you can reference characters in a string stream via their position in the string using array syntax: `varname[ position ]`. Please note that string and array positions in CFML start at 1 and not 0. ```javascript name = "luis"; writeoutput( name[ 1 ] ) => will produce l ``` Adobe has taken this further, and you can use negative indices to get characters from the end backward: ```javascript name = "luis"; writeoutput( name[ -1 ] ) => will produce s ``` ## Character Extractions by Range Adobe 2018+ also supports extraction as ranges using the following array syntax: ```javascript array[ start:stop:step ] ``` Which is extremely useful for doing character extractions in ranges ```javascript data = "Hello CFML. You Rock!"; writeOutput( data[ 1 ] ) // Returns H writeOutput( data[ -3 ] ) // Returns c writeOutput( data[ 4:10:2 ] ) // Returns l FL writeOutput( data[ 4:12 ] ) // Returns lo CFML writeOutput( data[ -10:-4:2]) // Returns o o ``` ## Common String Functions You can find all the available string functions here: . Below are some common ones that are handy to memorize: ### Len Call `len()` on a string to get back the number of characters in the string. For instance `Len( "Hello ")` would give you back **6** (notice the trailing space is counted). You can also use member functions: `a.len()`. ```javascript message = "Hola Luis" writeOutput( message.len() ) if( len( message ) ){ } ``` ### Trim, LTrim, RTrim The`Trim` function removes leading and trailing spaces and controls characters from a string. You can also use the `ltrim()` to do left trimming and `rtrim()` to do right trimming. For instance, `Trim("Hello ")` would give you back `Hello` (notice the trailing space is removed). Combine this with `Len` for example `Len( Trim( "Hello ") )` and you would get back `5`. You can also use member functions: ```javascript a.trim().len() ``` ### Replace, ReplaceNoCase, REReplace, REReplaceNoCase The `Replace` instruction replaces occurrences of **substring1** in a string with **substring2**, in a specified scope. The search is case-sensitive and the scoped default is one. If you would like the searches to be case-insensitive just use the `noCase()` suffix. For instance, `Replace("Hello", "l", "")` would give you back **Helo** after replacing the *first occurrence of l*, or `Replace("Good Morning!", "o", "e", "All")` would give you **Geed Merning!** `REReplace(), REReplaceNoCase()` are the same functions but using regular expressions: ```javascript reReplace( "test 123!", "[^a-z0-9]", "", "ALL" ) reReplace( "123abc456", "[0-9]+([a-z]+)[0-9]+", "\1" ) ``` ### RemoveChars `RemoveChars` will remove characters from a string. For instance, `RemoveChars("hello bob", 2, 5)` would give you back **hbob**. ### Mid The `mid` function extracts a substring from a string. For instance, I could call `Mid("Welcome to CFML Jumpstart", 4, 12)` and it would give you back: **come to CFML**. ```javascript s = "20001122" writedump( mid( s, 5, 2 ) ) // You can also use character extraction writedump( s[ 5:6 ] ) ``` ### ListToArray Another great function is `listToArray()` which can take any string and convert it to an array according to a delimiter, empty fields, and even multi-character delimiters. The default delimiter is a comma `,`, but you can use any one or a combination of characters. ```javascript a = "luis,majano,lucas,alexia,veronica"; myArray = a.listToArray(); // Multi-character delimiter list = "coldfusion,php,|test,java,|sql"; getArray = listToArray(list,",|",false,true); someJSON = serializeJSON(getArray); writeOutput(someJSON); ``` ## Combining Strings Combining and interpolating strings is part of any programming language and an integral part. We can do both by building upon some language [operators](/cfml-language/operators.md). If you have two or more strings, you can concatenate them by using the `&` operator: ```javascript name = "Luis"; a = "Hello " & name & " how are you today?"; ``` You can also concatenate and assign using the `&=` operator. Please [check out the operators](/cfml-language/operators.md#assignment-operators) section for more on string assignment operators. ## Interpolating Strings Interpolating is where we stick a string within another string. In CFML, we use the `#` hashes to output a variable to the stream in context. This means we can interpolate into any string: ```javascript name = "luis"; welcome = "Good morning #name#, how are you today?"; writeoutput( welcome ); ``` That's it! If you surround any **simple** variable with hashes, CFML will interpret the variable. Now try this with a complex variable and see what happens: ```javascript complex = [1,2,3]; welcome = "Good morning #complex#, how are you today (#now()#)?"; writeoutput( welcome ); ``` {% hint style="success" %} Please note that anything between hashes is interpreted as an expression in CFML. {% endhint %} ## Casting CFML also will try to automatically infer and auto-cast strings for you. However, there is a built-in function called `toString()` which can be used to try to convert any value to a string. ```javascript s = { "a": "1", "b":"2" }; writeOutput( toString(s) ) writeOutput( s.toString() ) number = 42222.222 writedump( number.toString() ) ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://modern-cfml.ortusbooks.com/cfml-language/strings.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. 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