Converting String Array to an Integer Array

Question

so basically user enters a sequence from an scanner input  12  3  4  etc  It can be of any length long and it has to be integers  I want to convert the string input to an integer array  so int 0  would be 12  int 1  would be 3  etc   Any tips and ideas  I was thinking of implementing if charat i         get the previous number s  and parse them together and apply it to the current available slot in the array  But I m not quite sure how to code that

User · Answer

Converting String array into stream and mapping to int is the best option available in java 8      String   stringArray   new String      quot 0 quot    quot 1 quot    quot 2 quot         int   intArray   Stream of stringArray  mapToInt Integer  parseInt  toArray        System out println Arrays toString intArray

User · Answer

Java has a method for this   quot convertStringArrayToIntArray quot   String numbers   sc nextLine    int   intArray   convertStringArrayToIntArray numbers split  quot    quot

User · Answer

Line by line  int    v   Stream of line split     s        mapToInt Integer  parseInt     toArray

User · Answer

import java util ArrayList  import java util List  import java util Scanner   class MultiArg        Scanner sc      int n      String as      List lt Integer gt  numList   new ArrayList lt Integer gt          public void fun             sc   new Scanner System in           System out println  enter value            while  sc hasNextInt                as   sc nextLine               public void diplay             System out println  x            Integer   num   numList toArray new Integer numList size              System out println  show value     as           for  Integer m   num                System out println   t    m                       but to terminate the while loop you have to put any charecter at the end of input   ex  input   12 34 56 78 45 67     output   12 34 56 78 45 67

User · Answer

You could read the entire input line from scanner  then split the line by   then you have a String    parse each number into int   with index one to one matching    assuming valid input and no NumberFormatExceptions  like  String line   scanner nextLine    String   numberStrs   line split       int   numbers   new int numberStrs length   for int i   0 i  lt  numberStrs length i            Note that this is assuming valid input       If you want to check then add a try catch        and another index for the numbers if to continue adding the others  see below     numbers i    Integer parseInt numberStrs i          As YoYo s answer suggests  the above can be achieved more concisely in Java 8   int   numbers   Arrays stream line split       mapToInt Integer  parseInt  toArray          To handle invalid input  You will need to consider what you want need to do in this case  do you want to know that there was bad input at that element or just skip it   If you don t need to know about invalid input but just want to continue parsing the array you could do the following   int index   0  for int i   0 i  lt  numberStrs length i          try               numbers index    Integer parseInt numberStrs i            index              catch  NumberFormatException nfe                  Do nothing or you could print error if you want            Now there will be a number of  invalid  elements     at the end which will need to be trimmed numbers   Arrays copyOf numbers  index     The reason we should trim the resulting array is that the invalid elements at the end of the int   will be represented by a 0  these need to be removed in order to differentiate between a valid input value of 0   Results in     Input   2 5 6 bad 10    Output   2 3 6 10    If you need to know about invalid input later you could do the following   Integer   numbers   new Integer numberStrs length   for int i   0 i  lt  numberStrs length i                  try                numbers i    Integer parseInt numberStrs i              catch  NumberFormatException nfe                   numbers i    null            In this case bad input  not a valid integer  the element will be null   Results in     Input   2 5 6 bad 10    Output   2 3 6 null 10      You could potentially improve performance by not catching the exception  see this question for more on this  and use a different method to check for valid integers

User · Answer

For Java 8 and higher      String   test     quot 1 quot    quot 2 quot    quot 3 quot    quot 4 quot    quot 5 quot        int   ints   Arrays stream test  mapToInt Integer  parseInt  toArray

User · Answer

Stream of   mapToInt   toArray   seems to be the best options   int   arr   Stream of new String    1    2    3                       mapToInt Integer  parseInt  toArray    System out println Arrays toString arr

[java] Converting String Array to an Integer Array

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