在Google Guava中打印HashBasedTable的所有键和值

Question

I create and populate a Guava Table using the following code:

Table<String, String, Integer> table = HashBasedTable.create();
table.put("A", "B", 1);
table.put("A", "C", 2);
table.put("B", "D", 3);

I wonder how to iterate over table and print out both keys and value for each row? So, the desired output is:

A B 1
A C 2
B D 3

Answer 1

Im not Guava user so this may be overkill (if it is true then will be glad for any info) but you can use table.rowMap() to get Map<String, Map<String, Integer>> which will represents data in table in form {A={B=1, C=2}, B={D=3}} . Then just iterate over this map like:

Map<String, Map<String, Integer>> map = table.rowMap();

for (String row : map.keySet()) {
    Map<String, Integer> tmp = map.get(row);
    for (Map.Entry<String, Integer> pair : tmp.entrySet()) {
        System.out.println(row+" "+pair.getKey()+" "+pair.getValue());
    }
}

or

for (Map.Entry<String, Map<String,Integer>> outer : map.entrySet()) {
    for (Map.Entry<String, Integer> inner : outer.getValue().entrySet()) {
        System.out.println(outer.getKey()+" "+inner.getKey()+" "+inner.getValue());
    }
}

or even better using com.google.common.collect.Table.Cell

for (Cell<String, String, Integer> cell: table.cellSet()){
    System.out.println(cell.getRowKey()+" "+cell.getColumnKey()+" "+cell.getValue());
}

Answer 2

you can use :

System.out.println(Arrays.asList(table));

and the output will be

[{A={B=1, C=2}, B={D=3}}]