问题
I am using ElasticSearch via NEST c#. I have large list of information about people
{
firstName: 'Frank',
lastName: 'Jones',
City: 'New York'
}
I'd like to be able to filter and sort this list of items by lastName as well as order by the length so people who only have 5 characters in their name will be at the beginning of the result set then people with 10 characters.
So with some pseudo code I'd like to do something like
list.wildcard("j*").sort(m => lastName.length)
I'm new to ElasticSearch so any examples would be super helpful.
回答1:
You can do the sorting with script-based sorting.
As a toy example, I set up a trivial index with a few documents:
PUT /test_index
POST /test_index/doc/_bulk
{"index":{"_id":1}}
{"name":"Bob"}
{"index":{"_id":2}}
{"name":"Jeff"}
{"index":{"_id":3}}
{"name":"Darlene"}
{"index":{"_id":4}}
{"name":"Jose"}
Then I can order search results like this:
POST /test_index/_search
{
"query": {
"match_all": {}
},
"sort": {
"_script": {
"script": "doc['name'].value.length()",
"type": "number",
"order": "asc"
}
}
}
...
{
"took": 2,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 4,
"max_score": null,
"hits": [
{
"_index": "test_index",
"_type": "doc",
"_id": "1",
"_score": null,
"_source": {
"name": "Bob"
},
"sort": [
3
]
},
{
"_index": "test_index",
"_type": "doc",
"_id": "4",
"_score": null,
"_source": {
"name": "Jose"
},
"sort": [
4
]
},
{
"_index": "test_index",
"_type": "doc",
"_id": "2",
"_score": null,
"_source": {
"name": "Jeff"
},
"sort": [
4
]
},
{
"_index": "test_index",
"_type": "doc",
"_id": "3",
"_score": null,
"_source": {
"name": "Darlene"
},
"sort": [
7
]
}
]
}
}
To filter by length, I can use a script filter in a similar way:
POST /test_index/_search
{
"query": {
"filtered": {
"query": {
"match_all": {}
},
"filter": {
"script": {
"script": "doc['name'].value.length() > 3",
"params": {}
}
}
}
},
"sort": {
"_script": {
"script": "doc['name'].value.length()",
"type": "number",
"order": "asc"
}
}
}
...
{
"took": 3,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 3,
"max_score": null,
"hits": [
{
"_index": "test_index",
"_type": "doc",
"_id": "4",
"_score": null,
"_source": {
"name": "Jose"
},
"sort": [
4
]
},
{
"_index": "test_index",
"_type": "doc",
"_id": "2",
"_score": null,
"_source": {
"name": "Jeff"
},
"sort": [
4
]
},
{
"_index": "test_index",
"_type": "doc",
"_id": "3",
"_score": null,
"_source": {
"name": "Darlene"
},
"sort": [
7
]
}
]
}
}
Here's the code I used:
http://sense.qbox.io/gist/22fef6dc5453eaaae3be5fb7609663cc77c43dab
P.S.: If any of the last names will contain spaces, you might want to use "index": "not_analyzed" on that field.
来源:https://stackoverflow.com/questions/29782450/elasticsearch-order-by-string-length