使用Lodash按键求值 [英] Using Lodash to sum values by key
本文介绍了使用Lodash按键求值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
如何对共享公共密钥的对象中的值求和?我需要使用Lodash,因为如果这些数组变得庞大,我需要良好的性能。
var prjMgrValues = [
{proj_mgr:Jack ProjManager,submitted_dollars:12000},
{proj_mgr:Jack ProjManager,submitted_dollars:750000},
{ proj_mgr:Joe ProjManager,submitted_dollars:45000}
]
I我正在寻找输出
[
{proj_mgr:Jack ProjManager,submitted_dollars: 762000},
{proj_mgr:Joe ProjManager,submitted_dollars:45000}
]
解决方案
这是每个独特元素减少的情况。
我总是使用 _。groupBy
然后 _。map
应用缩减后的数组结果。在这种情况下,还原操作是 _。sumBy
。
var prjMgrValues = [{proj_mgr:Jack ProjManager, submitted_dollars:12000},{proj_mgr:Jack ProjManager,submitted_dollars:750000},{proj_mgr:Joe ProjManager,submitted_dollars:45000}]; var output = _(prjMgrValues)。 groupBy('proj_mgr')。map((objs,key)=>({'proj_mgr':key,'submitted_dollars':_.sumBy(objs,'submitted_dollars')}))。value(); console.log (输出);
< script src =https: //cdn.jsdelivr.net/lodash/4.14.1/lodash.min.js\"></script>
How can I sum the values in objects which share a common key? I need to use Lodash for this because I need good performance if these arrays get huge.
var prjMgrValues = [
{"proj_mgr":"Jack ProjManager","submitted_dollars":12000},
{"proj_mgr":"Jack ProjManager","submitted_dollars":750000},
{"proj_mgr":"Joe ProjManager","submitted_dollars":45000}
]
I'm looking for an output of
[
{"proj_mgr":"Jack ProjManager","submitted_dollars":762000},
{"proj_mgr":"Joe ProjManager","submitted_dollars":45000}
]
解决方案
This is a case of reduction for each unique element.
I always use _.groupBy
and then _.map
the result to an array after applying the reduction. In this case the reduction operation is _.sumBy
.
var prjMgrValues = [
{"proj_mgr":"Jack ProjManager","submitted_dollars":12000},
{"proj_mgr":"Jack ProjManager","submitted_dollars":750000},
{"proj_mgr":"Joe ProjManager","submitted_dollars":45000}
];
var output =
_(prjMgrValues)
.groupBy('proj_mgr')
.map((objs, key) => ({
'proj_mgr': key,
'submitted_dollars': _.sumBy(objs, 'submitted_dollars') }))
.value();
console.log(output);
<script src="https://cdn.jsdelivr.net/lodash/4.14.1/lodash.min.js"></script>
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