How to find the minimum value in an ArrayList along with the index number Java

Question

I need to get the index value of the minimum value in my arraylist in Java  MY arraylist holds several floats  and I m trying to think of a way I can get the index number of the smallest float so I can use that index number elsewhere in my code  I m a beginner  so please don t hate me  Thanks

User · Answer

Here s what I do  I find the minimum first then after the minimum is found  it is removed from ArrayList    ArrayList lt Integer gt  a   new ArrayList lt  gt     a add 3   a add 6   a add 2   a add 5    while  a size    gt  0        int min   1000      for  int b a            if  b  lt  min              min   b            System out println  minimum      min       System out println  index of min      a indexOf  Integer  min        a remove  Integer  min

User · Answer

try this   public int getIndexOfMin List lt Float gt  data        float min   Float MAX VALUE      int index   -1      for  int i   0  i  lt  data size    i              Float f   data get i           if  Float compare f floatValue    min   lt  0                min   f floatValue                index   i                      return index

User · Answer

There is an easier way to find a min integer in array list   int min   array get 0           for  int i   array               min   min  lt  i   min   i

User · Answer

This should do it using built in functions   public static int minIndex  ArrayList lt Float gt  list      return list indexOf  Collections min list

User · Answer

You can use Collections min and List indexOf   int minIndex   list indexOf Collections min list      If you want to traverse the list only once  the above may traverse it twice    public static  lt T extends Comparable lt T gt  gt  int findMinIndex final List lt T gt  xs        int minIndex      if  xs isEmpty              minIndex   -1        else           final ListIterator lt T gt  itr   xs listIterator            T min   itr next       first element as the current minimum         minIndex   itr previousIndex            while  itr hasNext                  final T curr   itr next                if  curr compareTo min   lt  0                    min   curr                  minIndex   itr previousIndex                                      return minIndex

User · Answer

public static int minIndex  ArrayList lt Float gt  list      return list indexOf  Collections min list       System out println  quot Min    quot    list get minIndex list

User · Answer

You have to traverse the whole array and keep two auxiliary values     The minimum value you find  on your way towards the end  The index of the place where you found the min value   Suppose your array is called myArray  At the end of this code minIndex has the index of the smallest value   var min   Number MAX VALUE    the largest number possible in JavaScript var minIndex   -1   for  int i 0  i lt myArray length  i        if  myArray i   lt  min         min   myArray i         minIndex   i           This is assuming the worst case scenario  a totally random array  It is an O n  algorithm or order n algorithm  meaning that if you have n elements in your array  then you have to look at all of them before knowing your answer  O n  algorithms are the worst ones because they take a lot of time to solve the problem   If your array is sorted or has any other specific structure  then the algorithm can be optimized to be faster   Having said that  though  unless you have a huge array of thousands of values then don t worry about optimization since the difference between an O n  algorithm and a faster one would not be noticeable

[java] How to find the minimum value in an ArrayList, along with the index number? (Java)

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