> For the complete documentation index, see [llms.txt](https://boxlang.ortusbooks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://boxlang.ortusbooks.com/boxlang-language/reference/built-in-functions/struct/structinsert.md). # StructInsert Inserts a key/value pair in to a struct - with an optional overwrite argument ## Method Signature ``` StructInsert(struct=[modifiableStruct], key=[any], value=[any], overwrite=[boolean]) ``` ### Arguments | Argument | Type | Required | Description | Default | | ----------- | ------------------ | -------- | ---------------------------------------------------------------------------- | ------- | | `struct` | `modifiableStruct` | `true` | The target struct | | | `key` | `any` | `true` | The struct key | | | `value` | `any` | `true` | The value to assign for the specified key | | | `overwrite` | `boolean` | `false` | Whether to overwrite the existing value if the key exists ( default: false ) | `false` | ## Examples ### Simple Example Inserts a new key/value into the structure [Run Example](https://try.boxlang.io/?code=eJwli1EKgzAQBb%2BbUzz2q4InqHgAaaFnSNtFA5qG3Q0i4t2N%2BjUwzEw%2BocUKd6PBByE8QB%2F5z5HqonhhPVUvzJHc1jg1yV%2FrorLYHZNPNWgMSalQ%2BEeoGjdLMH5nS7kk1%2FDk5RX0OlAd0Q6fbSUY) ```java map = { "hair" : "brown", "eyes" : "green" }; structInsert( map, "lips", "red" ); writeOutput( structKeyList( map ) ); ``` Result: eyes,lips,hair ### Overwrite Example Throws exception when you try to add a duplicate key, when allowoverwrite parameter is false. [Run Example](https://try.boxlang.io/?code=eJwljEEOgjAQRdfMKb6zgoQTSDyAK89Q6ygkUprpNNgQ7m7F1Ute%2Fvuzi7hgAzU8ukkZZ%2FBdlzVwX5UUSYd6qUhg2gcyLdioSabZ2zUkUWsxu9jjf1Cp8qh4uncSdAPt8M78iNaFAvl0v3zVyeSWLeZas6gueuJjTF80fCtJ) ```java map = { "hair" : "brown", "eyes" : "green" }; try { structInsert( map, "hair", "red", false ); } catch (any ex) { writeOutput( "error!" ); } ``` Result: error! ### Additional Examples [Run Example](https://try.boxlang.io/?code=eJxljs0KwjAQhM%2FNUyx7qlDoXelBKkhPCj14jkmgwWQjaWIO4rvbPwvF4%2BzMfjOctOWmhwrewLL6coM9oHUOC5Zdm%2FOonKYHss%2BBlSW0nUsgoveKAvD5l52ifeZg%2BF2ZCuutiQW8uK8WBbuJ0lCvfADBA2gKbgW1wUcRZjf%2FXQvAIThw0CqXcEFMQ9YEDUKTMFGqfsRuJx2X8qRDN5VyKZX8X%2FYFW0NWfw%3D%3D) ```java animals = { COW : "moo", PIG : "oink" }; // Show current animals Dump( label="Current animals", var=animals ); // Insert cat into animals StructInsert( animals, "cat", "meow" ); // Show animals, now includes cat Dump( label="Animals with cat added", var=animals ); ``` ## Related * [StructAppend](/boxlang-language/reference/built-in-functions/struct/structappend.md) * [StructClear](/boxlang-language/reference/built-in-functions/struct/structclear.md) * [StructCopy](/boxlang-language/reference/built-in-functions/struct/structcopy.md) * [StructDelete](/boxlang-language/reference/built-in-functions/struct/structdelete.md) * [StructEach](/boxlang-language/reference/built-in-functions/struct/structeach.md) * [StructEquals](/boxlang-language/reference/built-in-functions/struct/structequals.md) * [StructEvery](/boxlang-language/reference/built-in-functions/struct/structevery.md) * [StructFilter](/boxlang-language/reference/built-in-functions/struct/structfilter.md) * [StructFind](/boxlang-language/reference/built-in-functions/struct/structfind.md) * [StructFindKey](/boxlang-language/reference/built-in-functions/struct/structfindkey.md) * [StructFindValue](/boxlang-language/reference/built-in-functions/struct/structfindvalue.md) * [StructGet](/boxlang-language/reference/built-in-functions/struct/structget.md) * [StructGetMetadata](/boxlang-language/reference/built-in-functions/struct/structgetmetadata.md) * [StructIsCaseSensitive](/boxlang-language/reference/built-in-functions/struct/structiscasesensitive.md) * [StructIsOrdered](/boxlang-language/reference/built-in-functions/struct/structisordered.md) * [StructKeyArray](/boxlang-language/reference/built-in-functions/struct/structkeyarray.md) * [StructKeyExists](/boxlang-language/reference/built-in-functions/struct/structkeyexists.md) * [StructKeyList](/boxlang-language/reference/built-in-functions/struct/structkeylist.md) * [StructKeyTranslate](/boxlang-language/reference/built-in-functions/struct/structkeytranslate.md) * [StructMap](/boxlang-language/reference/built-in-functions/struct/structmap.md) * [StructNew](/boxlang-language/reference/built-in-functions/struct/structnew.md) * [StructNone](/boxlang-language/reference/built-in-functions/struct/structnone.md) * [StructReduce](/boxlang-language/reference/built-in-functions/struct/structreduce.md) * [StructSome](/boxlang-language/reference/built-in-functions/struct/structsome.md) * [StructSort](/boxlang-language/reference/built-in-functions/struct/structsort.md) * [StructToQueryString](/boxlang-language/reference/built-in-functions/struct/structtoquerystring.md) * [StructToSorted](/boxlang-language/reference/built-in-functions/struct/structtosorted.md) * [StructUpdate](/boxlang-language/reference/built-in-functions/struct/structupdate.md) * [StructValueArray](/boxlang-language/reference/built-in-functions/struct/structvaluearray.md) --- # Agent Instructions This documentation is published with GitBook. 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