Java:将数组解析为正数组和负数组
下面是我所做的,它工作正常,但我不想固定数量的正负文章,因此代码可以在任何数组上工作:Java:将数组解析为正数组和负数组,java,arrays,Java,Arrays,下面是我所做的,它工作正常,但我不想固定数量的正负文章,因此代码可以在任何数组上工作: int[] array = {15, 22, 71, -27, 33, -44, 0, 334, -82}; int[] negative = new int[3]; int[] positive = new int[6]; int n = 0; int p = 0; for(int i=0;i<array.length;i++){ if
int[] array = {15, 22, 71, -27, 33, -44, 0, 334, -82};
int[] negative = new int[3];
int[] positive = new int[6];
int n = 0;
int p = 0;
for(int i=0;i<array.length;i++){
if(array[i]<0){
negative[n] = array[i];
n++;
}else{
positive[p] = array[i];
p++;
}
}
System.out.println("Negative array : " + Arrays.toString(negative));
System.out.println("Positive array : " + Arrays.toString(positive));
int[]数组={15,22,71,-27,33,-44,0334,-82};
int[]负=新的int[3];
int[]正=新的int[6];
int n=0;
int p=0;
对于(int i=0;i使用列表,它没有固定大小:
int[] array = {15, 22, 71, -27, 33, -44, 0, 334, -82};
List<Integer> negative = new ArrayList<>();
List<Integer> positive = new ArrayList<>();
for(int i = 0;i<array.length;i++){
if(array[i]<0){
negative.add(array[i]); // Add negative number
}else{
positive.add(array[i]); // Add positive number
}
}
int[]数组={15,22,71,-27,33,-44,0334,-82};
List negative=new ArrayList();
List positive=new ArrayList();
对于(int i=0;i您可以采用两种不同的方法:
- 在第一步计算负和正,生成负和正的数组并填充它们
- 为正片和负片创建
列表
,填充它们并将它们转换为数组
如果不需要正片和负片数组,也可以将原始数组拆分为两个列表(而不是两个数组)
第一种可能性
int numPositives = 0;
int numNegatives = 0;
for(int i=0;i<array.length;i++){
if (array[i] >= 0) {
numPositives++;
} else {
numNegatives++;
}
}
int[] negative = new int[numNegatives];
int[] positive = new int[numPositives];
int n = 0;
int p = 0;
for(int i=0;i<array.length;i++){
if(array[i]<0){
negative[n] = array[i];
n++;
}else{
positive[p] = array[i];
p++;
}
}
List<Integer> positivesList = new ArrayList<Integer>();
List<Integer> negativesList = new ArrayList<Integer>();
for (int i = 0; i < array.length; i++) {
if (array[i] >= 0) {
positivesList.add(array[i]);
} else {
negativesList.add(array[i]);
}
}
int[] positive = positivesList.toArray(new int[positivesList.size()]);
int[] negative = negativesList.toArray(new int[negativesList.size()]);
int numPositives=0;
int numNegatives=0;
对于(int i=0;i=0){
numPositives++;
}否则{
numNegatives++;
}
}
int[]负=新的int[numNegatives];
int[]正数=新的int[numPositives];
int n=0;
int p=0;
对于(int i=0;iJava 8引入了包含lambda谓词过滤的流:
int[] pos = Arrays.stream(array).filter((int i) -> i >= 0).toArray();
int[] neg = Arrays.stream(array).filter((int i) -> i < 0).toArray();
int[]pos=Arrays.stream(array).filter((inti)->i>=0.toArray();
int[]neg=Arrays.stream(array).filter((inti)->i<0.toArray();
这里有一个小解决方案,它不涉及列表,也不预先计算负值的数量。它更像是使用本机解决方案来复制尚未找到的值。我还对其进行了更改,以便将负值和正值存储在单个2d数组中
public static void main(String[] args) {
int[] array = {15, 22, 71, -27, 33, -44, 0, 334, -82};
int[][] vals = new int[2][0];
for(int i=0;i<array.length;i++){
if(array[i]<0){
int[] buffer = new int[vals[0].length+1]; // create array with one more value
System.arraycopy(vals[0], 0, buffer, 0, vals[0].length); // Copy old values
buffer[buffer.length-1] = array[i]; // assign new value
vals[0] = buffer; // assign old and new values
} else {
int[] buffer = new int[vals[1].length+1]; // create array with one more value
System.arraycopy(vals[1], 0, buffer, 0, vals[1].length); // Copy old values
buffer[buffer.length-1] = array[i]; // assign new value
vals[1] = buffer; // assign old and new values
}
}
System.out.println("Negative array : " + Arrays.toString(vals[0]));
System.out.println("Positive array : " + Arrays.toString(vals[1]));
}
publicstaticvoidmain(字符串[]args){
int[]数组={15,22,71,-27,33,-44,0334,-82};
int[]vals=新int[2][0];
对于(int i=0;i根据@davide,两种方法均可使用
1) 在第一步计算负和正,生成负和正的数组并填充它们
int numPositives = 0;// davide example
int numNegatives = 0;
for(int i=0;i<array.length;i++){
if (array[i] >= 0) {
numPositives++;
} else {
numNegatives++;
}
}
int[] negative = new int[numNegatives];
int[] positive = new int[numPositives];
int n = 0;
int p = 0;
for(int i=0;i<array.length;i++){
if(array[i]<0){
negative[n] = array[i];
n++;
}else{
positive[p] = array[i];
p++;
}
}
我想要两个数组,而不是列表。如何生成正负数组?
int[] array = {15, 22, 71, -27, 33, -44, 0, 334, -82};
List<Integer> negativeList = new ArrayList<>();
List<Integer> positiveList = new ArrayList<>();
for(int i = 0;i<array.length;i++){
if(array[i]<0){
negativeList.add(array[i]); // Add negative number
}else{
positiveList.add(array[i]); // Add positive number
}
}
int negativeArray[] = negativeList.stream().mapToInt(i->i).toArray();
int positiveArray[] = negativeList.stream().mapToInt(i->i).toArray();