[英]How to get first and last element in an array in java?
如果我有一個雙打數組:
[10.2, 20, 11.1, 21, 31, 12, 22.5, 32, 42, 13.6, 23, 32, 43.3, 53, 14, 24, 34, 44, 54, 64, 15.1, 25, 35, 45, 55, 65.3, 75.4, 16, 26, 17.5,]
我想獲取第一個元素和最后一個元素,以便
firstNum = 10.2
lastNum = 17.5
我該怎么做?
如果您有一個名為numbers
的雙數組,則可以使用:
firstNum = numbers[0];
lastNum = numbers[numbers.length-1];
或使用ArrayList
firstNum = numbers.get(0);
lastNum = numbers.get(numbers.size() - 1);
在Java中獲取數組中的第一個和最后一個元素
int[] a = new int[]{1, 8, 5, 9, 4};
First Element: a[0]
Last Element: a[a.length-1]
// Array of doubles
double[] array_doubles = {2.5, 6.2, 8.2, 4846.354, 9.6};
// First position
double firstNum = array_doubles[0]; // 2.5
// Last position
double lastNum = array_doubles[array_doubles.length - 1]; // 9.6
這在任何數組中都是一樣的。
檢查這個
double[] myarray = ...;
System.out.println(myarray[myarray.length-1]); //last
System.out.println(myarray[0]); //first
我認為只有一種直觀的解決方案,它是:
int[] someArray = {1,2,3,4,5};
int first = someArray[0];
int last = someArray[someArray.length - 1];
System.out.println("First: " + first + "\n" + "Last: " + last);
輸出:
First: 1
Last: 5
double[] numbers = {10.2, 20, 11.1, 21, 31, 12,
22.5, 32, 42, 13.6, 23, 32, 43.3, 53, 14, 24, 34,
44, 54, 64, 15.1, 25, 35, 45, 55, 65.3, 75.4, 16, 26, 17.5,};
double firstNumber= numbers[0];
double lastNumber = numbers[numbers.length-1];
System.out.println("firstNum = "+ firstNumber);
System.out.println("lastNum = "+ lastNumber);
這是給定的數組。
int myIntegerNumbers[] = {1,2,3,4,5,6,7,8,9,10};
// 如果要打印數組中的最后一個元素。
int lastNumerOfArray= myIntegerNumbers[9];
Log.i("MyTag", lastNumerOfArray + "");
// 如果要打印數組中元素的數量。
Log.i("MyTag", "The number of elements inside" +
"the array " +myIntegerNumbers.length);
// 打印數組中最后一個元素的第二種方法。
Log.i("MyTag", "The last elements inside " +
"the array " + myIntegerNumbers[myIntegerNumbers.length-1]);
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