基于JTable创建HashMap [英] create the HashMap based on JTable
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问题描述
有 JTable
以下内容
Col1 | Col2
A | 1
A | 2
A | 3
B | 5
B | 1
C | 5
C | 4
C | 2
基于此表,我需要创建一个 HashMap数字
:第1列指键,第2列指数据。
下面我提供了我的代码片段。问题是:有没有更快的方法来创建所提到的HashMap?
HashMap numbers = new HashMap< String,List< String> ;>();
for(int i = 0; i< tbNumbers.getRowCount(); i ++)
{
col1 = mdNumbers.getValueAt(i,0).toString();
col2Array = new ArrayList< String>();
for(int j = 0; j {
if(mdNumbers.getValueAt(j,0).toString()== col1)
{
col2Array.add(mdNumbers.getValueAt(j,1).toString());
}
}
numbers.put(col1,col2Array);
$ div $解析方案
是的,可以让HashMap做这项工作,而不是使用嵌套循环。
HashMap numbers = new HashMap< String,List< String> >();
List col2Array = null;
for(int i = 0; i< tbNumbers.getRowCount(); i ++)
{
col1 = mdNumbers.getValueAt(i,0).toString();
col2Array = numbers.get(col1);
if(col2Array == null){
col2Array = new ArrayList< String>();
numbers.put(col1,col2Array);
}
col2Array.add(mdNumbers.getValueAt(i,1).toString());
}
There is JTable
with the following content
Col1 | Col2
A | 1
A | 2
A | 3
B | 5
B | 1
C | 5
C | 4
C | 2
Based on this table, I need to create a HashMap numbers
: column 1 refers to keys and column 2 refers to data.
Below I provide my code snippet. The question is: is there any quicker way to create the mentioned HashMap?
HashMap numbers = new HashMap<String, List<String>>();
for (int i=0; i<tbNumbers.getRowCount(); i++)
{
col1 = mdNumbers.getValueAt(i,0).toString();
col2Array = new ArrayList<String>();
for (int j=0; j<tbNumbers.getRowCount(); j++)
{
if (mdNumbers.getValueAt(j,0).toString() == col1)
{
col2Array.add(mdNumbers.getValueAt(j,1).toString());
}
}
numbers.put(col1, col2Array);
}
解决方案
Yes, maybe let the HashMap do the work instead of using a nested loop.
HashMap numbers = new HashMap<String, List<String>>();
List col2Array=null;
for (int i=0; i<tbNumbers.getRowCount(); i++)
{
col1 = mdNumbers.getValueAt(i,0).toString();
col2Array = numbers.get(col1);
if(col2Array==null){
col2Array=new ArrayList<String>();
numbers.put(col1,col2Array);
}
col2Array.add(mdNumbers.getValueAt(i,1).toString());
}
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