java程序返回在参数String中找到的所有整数的总和
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java program to return the sum of all integers found in the parameter String
提问by preeth
i want write a java program to return the sum of all integers found in the parameter String. for example take a string like:" 12 hi when 8 and 9" now the answer is 12+8+9=29. but i really dont know even how to start can any one help in this!
我想编写一个java程序来返回参数字符串中找到的所有整数的总和。例如，取这样的字符串：“12 hi when 8 and 9”现在答案是 12+8+9=29。但我真的不知道如何开始，任何人都可以帮助解决这个问题！
采纳答案by Baby
You may start with replacing all non-numbers from the stringwith space, and spiltit based on the space
您可以从替换所有非数字开始string使用space，并且spilt它的基础上的space
String str = "12 hi when 8 and 9";
str=str.replaceAll("[\D]+"," ");
String[] numbers=str.split(" ");
int sum = 0;
for(int i=0;i<numbers.length;i++){
try{
sum+=Integer.parseInt(numbers[i]);
}
catch( Exception e ) {
//Just in case, the element in the array is not parse-able into Integer, Ignore it
}
}
System.out.println("The sum is:"+sum);
回答by Sanjeev
You shall use Scanner to read your string
您应使用 Scanner 读取您的字符串
Scanner s = new Scanner(your string);
And then read it using
然后使用阅读它
s.nextInt();
Then add these integers.
然后将这些整数相加。
回答by barak manos
Here is the general algorithm:
下面是通用算法：
- Initialize your sum to zero.
- Split the string by spaces, and for each token:
- Try to convert the token into an integer.
- If no exception is thrown, then add the integer to your sum.
- 将您的总和初始化为零。
- 按空格分割字符串，并为每个标记：
- 尝试将令牌转换为整数。
- 如果没有抛出异常，则将整数添加到您的总和中。
And here is a coding example:
这是一个编码示例：
int sumString(String input)
{
int output = 0;
for (String token : input.split(" "))
{
try
{
output += Integer.parseInt(token);
}
catch (Exception error)
{
}
}
return output;
}
回答by anand mahuli
private static int getSumOfIntegersInString(String string) {
/*Split the String*/
String[] stringArray = string.split(" ");
int sum=0;
int temp=0;
for(int i=0;i<stringArray.length;i++){
try{
/*Convert the numbers in string to int*/
temp = Integer.parseInt(stringArray[i]);
sum += temp;
}catch(Exception e){
/*ignore*/
}
}
return sum;
}
回答by Salix alba
You could use a regular expression
你可以使用正则表达式
Pattern p = Pattern.compile("\d+");
String s = " 12 hi when 8 and 9" ;
Matcher m = p.matcher(s);
int start = 0;
int sum=0;
while(m.find(start)) {
String n = m.group();
sum += Integer.parseInt(n);
start = m.end();
}
System.out.println(sum);
This approach does not require the items to be separated by spaces so it would work with "12hiwhen8and9".
这种方法不需要用空格分隔项目，因此它可以与“12hiwhen8and9”一起使用。
回答by yellowB
Assume your words are separated by whitespace(s)：
假设您的单词由空格分隔：
Then split your input string into "tokens"(continuous characters without whitespace). And then loop them, try to convert each of them into integer, if exception thrown, means this token doesn't represents a integer.
然后将您的输入字符串拆分为“令牌”（没有空格的连续字符）。然后循环它们，尝试将它们中的每一个转换为整数，如果抛出异常，则表示此标记不代表整数。
Code:
代码：
public static int summary(String s) {
String[] tokens = s.split("\s+");
int sum = 0;
for(String token : tokens) {
try {
int val = Integer.parseInt(token);
sum += val;
}
catch(NumberFormatException ne){
// Do nothing
}
}
return sum;
}
回答by java.mypassion
String s ="12 hi when 8 and 9";
s=s.replaceAll("[^0-9]+", " ");
String[] numbersArray= s.split(" ");
Integer sum = 0;
for(int i = 0 ; i<numbersArray.length;i++){
if(numbersArray[i].trim().length() != 0){
Integer value = Integer.valueOf(numbersArray[i].trim());
sum = sum + value;
}
}
System.out.println(sum);
回答by Chandan Mishra
You can have a look on the following code :-
您可以查看以下代码：-
public class Class02
{
public static void main(String[] args)
{
String str = "12 hi when 8 and 9";
int sum = 0;
List<String> list = new ArrayList<String>();
StringTokenizer st = new StringTokenizer(str.toLowerCase());
while(st.hasMoreElements())
{
list.add(st.nextToken());
}
for(int i =0; i< list.size();i++)
{
char [] array = list.get(i).toCharArray();
int num = array[0];
if(!(num >= 'a' && num <= 'z'))
{
int number = Integer.valueOf((list.get(i).toString()));
sum = sum + number;
}
}
System.out.println(sum);
}
}
Hope it will help you.
希望它会帮助你。
回答by Kannan Ekanath
I understand that this does not have the Java8 tag but I will put this out there in case someone finds it interesting
我知道这没有 Java8 标签，但我会把它放在那里以防有人觉得它很有趣
String str = "12 hi when 8 and 9";
System.out.println(Arrays.stream(str.split(" "))
.filter(s -> s.matches("[0-9]+")).mapToInt(Integer::parseInt).sum());
would nicely print out 29
会很好地打印出 29
