# hmy\_newFilter

Creates a filter object, based on filter options, to notify when the state changes (logs). To check if the state has changed, call hmy\_getFilterChanges

**A note on specifying topic filters:**

Topics are order-dependent. A transaction with a log with topics \[A, B] will be matched by the following topic filters:

* `[]` "anything"
* `[A]` "A in first position (and anything after)"
* `[null, B]` "anything in first position AND B in second position (and anything after)"
* `[A, B]` "A in first position AND B in second position (and anything after)"
* `[[A, B], [A, B]]` "(A OR B) in first position AND (A OR B) in second position (and anything after)"

**Parameters**

1. `Object` - The filter options:
2. `fromBlock`: `QUANTITY|TAG` - (optional, default: `"latest"`) Integer block number, or `"latest"` for the last mined block or `"pending"`, `"earliest"` for not yet mined transactions.
3. `toBlock`: `QUANTITY|TAG` - (optional, default: `"latest"`) Integer block number, or `"latest"` for the last mined block or `"pending"`, `"earliest"` for not yet mined transactions.
4. `address`: `DATA|Array`, 20 Bytes - (optional) Contract address or a list of addresses from which logs should originate.
5. `topics`: `Array of DATA`, - (optional) Array of 32 Bytes `DATA` topics. Topics are order-dependent. Each topic can also be an array of DATA with "or" options.

**Example Parameters**

```
params: [{
  "fromBlock": "0x1",
  "toBlock": "0x2",
  "address": "0x8888f1f195afa192cfee860698584c030f4c9db1",
  "topics": ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", null, ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", "0x0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc"]]
}]
```

**Returns**

`QUANTITY` - A filter id.

**Example**

```
// Request
curl -d '{"jsonrpc":"2.0","method":"hmy_newFilter","params":[{"topics":["0x0000000000000000000000000000000000000000000000000000000012341234"]}],"id":73}' -H "Content-Type:application/json" -X POST "https://api.s0.b.hmny.io"

// Result
{
  "id":1,
  "jsonrpc": "2.0",
  "result": "0x1" // 1
}
```