hashMapOf()是HashMap类的函数。它返回具有指定内容的新HashMap。它包含键和值形式的数据对。 HashMap是可变集合, 可提供读写功能。
hashMapOf()函数的语法

inline fun < K, V> hashMapOf(): HashMap< K, V> (source)

fun < K, V> hashMapOf(vararg pairs: Pair< K, V> ): HashMap< K, V> (source)

Kotlin HashMap类的功能

功能	描述
打开趣味看跌期权（键：K, 值：V）：V？	它将指定的键和值放入地图中
打开运算符fun get（key：K）：V？	它返回指定键的值；如果map中没有这样的指定键, 则返回null。
打开乐趣containsKey（key：K）：布尔值	如果map包含指定键, 则返回true。
打开乐趣containsValue（value：V）：布尔值	如果map将多个键之一映射到指定值, 则返回true。
open fun clear()	它从地图中删除所有元素。
打开乐趣删除（键：K）：V？	它从映射中删除指定的键及其对应的值

Kotlin hashMapOf()示例1
HashMap的hashMapOf()函数可以声明为不同的通用类型, 例如hashMapOf < Int, String> (), hashMapOf < String, String> (), hashMapOf < Any, Any> ()等。

fun main(args: Array< String> ){val intMap: HashMap< Int, String> = hashMapOf< Int, String> (1 to "Ashu", 4 to "Rohan", 2 to "Ajeet", 3 to "Vijay")val stringMap: HashMap< String, String> = hashMapOf< String, String> ("name" to "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")val anyMap: HashMap< Any, Any> = hashMapOf< Any, Any> (1 to "Ashu", "name" to "Rohsan", 2 to 200)println(".....traverse intMap........")for(key in intMap.keys){println(intMap[key])}println("......traverse stringMap.......")for(key in stringMap.keys){println(stringMap[key])}println("......traverse anyMap.......")for(key in anyMap.keys){println(anyMap[key])}}

输出：

.....traverse intMap........AshuAjeetVijayRohan......traverse stringMap.......AshuDevelopmentDelhiPlaying......traverse anyMap.......RohsanAshu200

Kotlin hashMapOf()示例2-containsKey()
如果containsKey()函数在HashMap中包含提及键, 则返回true, 否则返回false。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println("......stringMap.containsKey(\"name\").......")println(stringMap.containsKey("name"))}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing......stringMap.containsKey("name").......true

Kotlin hashMapOf()示例3-containsValue()
如果containsValue()函数在HashMap中包含提及值, 则返回true, 否则返回false。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println(".......stringMap.containsValue(\"Delhi\")......")println(stringMap.containsValue("Delhi"))println(stringMap.containsValue("Mumbai"))}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing.......stringMap.containsValue("Delhi")......truefalse

Kotlin hashMapOf()示例4-contains()
如果contains()函数在HashMap中包含提及键, 则返回true, 否则返回false。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println("......stringMap.contains(\"city\").......")println(stringMap.contains("city"))}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing......stringMap.contains("city").......true

Kotlin hashMapOf()示例5-replace（key, value）
replace（key, value）函数用于用新的指定值替换指定键处的现有值。 replace（key, value）函数返回替换后的值。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println("......stringMap.replace(\"city\", \"Mumbai\").......")println(stringMap.replace("city", "Mumbai"))println("......traverse stringMap after stringMap.replace(\"city\", \"Mumbai\").......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing......stringMap.replace("city", "Mumbai").......Delhi......traverse stringMap after stringMap.replace("city", "Mumbai").......Key = city , value = http://www.srcmini.com/MumbaiKey = name , value = http://www.srcmini.com/AshuKey = department , value = DevelopmentKey = hobby , value = Playing

Kotlin hashMapOf()示例6-replace（key, oldValue, newValue）
replace（key, oldValue, newValue）函数用于用新的指定值替换指定键处的现有旧值。如果将旧值替换为新值, 则replace（key, newValue, oldValue）函数返回true, 否则返回false。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println(".......stringMap.replace(\"department\", \"Development\", \"Management\")......")println(stringMap.replace("department", "Development", "Management"))println("......traverse stringMap after stringMap.replace(\"department\", \"Development\", \"Management\").......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing.......stringMap.replace("department", "Development", "Management")......true......traverse stringMap after stringMap.replace("department", "Development", "Management").......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = ManagementKey = hobby , value = Playing

Kotlin hashMapOf()示例7-hashMapOf()。size, hashMapOf()。key
hashMapOf()函数的size属性返回HashMap的总大小, 而key属性返回HashMap的所有键。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println(".....stringMap.size........")println(stringMap.size)println(".......stringMap.keys......")println(stringMap.keys)}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing.....stringMap.size........4.......stringMap.keys......[city, name, department, hobby]

Kotlin hashMapOf()示例8-getValue（key）, getOrDefault（key, defaultValue）
getValue()函数返回HashMap的指定键的值。而getOrDefault()函数返回指定键的对应值（如果该键存在于HashMap中）, 或者返回所提及的默认值（如果HashMap中不存在这样的键）。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println(".......stringMap.getValue(\"department\")......")println(stringMap.getValue("department"))println(".......stringMap.getOrDefault(\"name\", \"Default Value\")......")println(stringMap.getOrDefault("name", "Default Value"))}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing.......stringMap.getValue("department")......Development.......stringMap.getOrDefault("name", "Default Value")......Ashu

Kotlin hashMapOf()示例9-remove（key）
remove（key）函数用于删除指定的键及其对应的值。 remove（key）函数返回删除的值。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println("......stringMap.remove(\"city\").......")println(stringMap.remove("city"))println("......traverse stringMap after stringMap.remove(\"city\").......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing......stringMap.remove("city").......Delhi......traverse stringMap after stringMap.remove("city").......Key = name , value = http://www.srcmini.com/AshuKey = department , value = DevelopmentKey = hobby , value = Playing

Kotlin hashMapOf()示例10-remove（key, value）
remove（key, value）函数用于删除指定的键及其对应的值。如果remove（key, value）函数将指定的键及其值一起移除, 则返回true, 否则返回false。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println(".......stringMap.remove(\"hobby\", \"Playing\")......")println(stringMap.remove("hobby", "Playing"))println("......traverse stringMap after stringMap.remove(\"hobby\", \"Playing\").......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing.......stringMap.remove("hobby", "Playing")......true......traverse stringMap after stringMap.remove("hobby", "Playing").......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = Development

Kotlin hashMapOf()示例11-set（key, value）
set（key, value）函数用于设置指定键处的给定值（如果存在）。如果该密钥在HashMap中不存在, 它将添加新密钥并设置与之对应的给定值。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}stringMap.set("name", "Ashutosh")stringMap.set("skill", "Kotlin")println("......traverse stringMap after stringMap.set(\"name\", \"Ashutosh\") andstringMap.set(\"skill\", \"Kotlin\").......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}}

输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing......stringMap.set("name", "Ashutosh").............traverse stringMap after stringMap.set("name", "Ashutosh") and stringMap.set("skill", "Kotlin").......Key = city , value = http://www.srcmini.com/DelhiKey = skill , value = KotlinKey = name , value = AshutoshKey = department , value = DevelopmentKey = hobby , value = Playing

Kotlin hashMapOf()示例12-clear()
clear()函数用于从HashMap中清除（或删除）所有键值对。

fun main(args: Array< String> ){val stringMap: HashMap< String, String> = hashMapOf< String, String> ()stringMap.put("name", "Ashu")stringMap.put("city", "Delhi")stringMap.put("department", "Development")stringMap.put("hobby", "Playing")println("......traverse stringMap.......")for(key in stringMap.keys){println("Key = ${key} , value = http://www.srcmini.com/${stringMap[key]}")}println("......stringMap.clear().......")println(stringMap.clear())println(stringMap)}

【Kotlin HashMap（hashMapOf()）】输出：

......traverse stringMap.......Key = city , value = http://www.srcmini.com/DelhiKey = name , value = AshuKey = department , value = DevelopmentKey = hobby , value = Playing......stringMap.clear().......kotlin.Unit{}

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