collections

问题 I have below HashMap(to.String()) printed below. HashMap<String, HashMap<String, HashMap<String, Integer>>> abc = new HashMap<>(); HashMap abc = {disabled={account={testConfiguration=1, iterate=1}}} I want to append {group={iterate=1}} to existing map if key disabled matches. Finally my map should look like below, how can I achieve it? HashMap abc = {disabled={account={testConfiguration=1, iterate=1}, {group={iterate=1}}} 回答1: I think you want this: abc.computeIfPresent("disabled", (k,v) -> {

问题 Suppose I have data coming as json in the below format [ { "clauseId": 1, "clauseName": "cover", "texts": [ { "textId": 1, "text": "hello" } ] }, { "clauseId": 3, "clauseName": "xyz", "texts": [ { "textId": 3, "text": "hello Everyone" }, { "textId": 4, "text": "Some data" } ] } { "clauseId": 2, "clauseName": "joining", "texts": [ { "textId": 3, "text": "hello1" }, { "textId": 4, "text": "hello2" } ] } ] I have made a list from clause Name like c=[joining,xyz] I want to make a list where the

问题 I have a pretty simple user settings form: <form:form method="post" id="fm1" cssClass="fm-v clearfix" commandName="${commandName}" htmlEscape="true"> <div class="row fl-controls-left"> <spring:message code="screen.userSettings.label.timeZone.accesskey" var="timeZoneAccessKey" /> <label for="timeZone" class="fl-label"><spring:message code="screen.userSettings.label.timeZone" /></label> <form:select id="timeZone" path="timeZone" accesskey="${timeZoneAccessKey}"> <form:options items="${user

问题 I have a pretty simple user settings form: <form:form method="post" id="fm1" cssClass="fm-v clearfix" commandName="${commandName}" htmlEscape="true"> <div class="row fl-controls-left"> <spring:message code="screen.userSettings.label.timeZone.accesskey" var="timeZoneAccessKey" /> <label for="timeZone" class="fl-label"><spring:message code="screen.userSettings.label.timeZone" /></label> <form:select id="timeZone" path="timeZone" accesskey="${timeZoneAccessKey}"> <form:options items="${user

问题 The code below is for the ArrayList of String. I want to know what's the complexity of the Collections.frequency() function. List<String> list = new ArrayList<>(); list.add("sample"); list.add("sample1"); list.add("sample"); list.add("sample"); list.add("sample"); list.add("sample"); System.out.println("sample is repeated : " + Collections.frequency(list, "sample")); 回答1: Collections.frequency has the following implementation (in Java 9): public static int frequency(Collection<?> c, Object o)

问题 Judging from the result of my last inquiry, I need to calculate and preset the widths of a set of columns in a table that is being made into an Excel file. Unfortunately, the string data is stored in a row-based format, but the widths must be calculated in a column-based format. The data for the spreadsheets are generated from the following two collections: var dictFiles = l.Items.Cast<SPListItem>().GroupBy(foo => foo.GetSafeSPValue("Category")).ToDictionary(bar => bar.Key); StringDictionary

问题 I read online that HashSet uses HashMap as its underlying data structure. And HashMap uses ArrayList as its underlying data structure with each item in the list being an object of LinkedList or a tree . What is the time complexity when you initialize a HashSet this way? Can it be O(1) ? If not, why? List<Integer> list = new ArrayList<>(); list.add(1); list.add(3); list.add(2); list.add(6); list.add(0); HashSet<Integer> set = new HashSet<>(list); 回答1: HashMap does not use an ArrayList as its

问题 I read online that HashSet uses HashMap as its underlying data structure. And HashMap uses ArrayList as its underlying data structure with each item in the list being an object of LinkedList or a tree . What is the time complexity when you initialize a HashSet this way? Can it be O(1) ? If not, why? List<Integer> list = new ArrayList<>(); list.add(1); list.add(3); list.add(2); list.add(6); list.add(0); HashSet<Integer> set = new HashSet<>(list); 回答1: HashMap does not use an ArrayList as its

问题 I read online that HashSet uses HashMap as its underlying data structure. And HashMap uses ArrayList as its underlying data structure with each item in the list being an object of LinkedList or a tree . What is the time complexity when you initialize a HashSet this way? Can it be O(1) ? If not, why? List<Integer> list = new ArrayList<>(); list.add(1); list.add(3); list.add(2); list.add(6); list.add(0); HashSet<Integer> set = new HashSet<>(list); 回答1: HashMap does not use an ArrayList as its

问题 I have this class: public class Friend { private String name; private String location; private String temp; private String humidity; public String getTemp() { return temp; } public void setTemp(String temp) { this.temp = temp; } public String getHumidity() { return humidity; } public void setHumidity(String humidity) { this.humidity = humidity; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getLocation() { return location; }