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How to find average using map reduce in MongoDB?
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3
My document is of format:
{
"PItems": {
"Workspaces": [
{
"Key": "Item1",
"Size": 228.399,
"Foo": "bar"
},
{
"Key": "Item2",
"Size": 111.399,
"Bar": "baz"
},
{
"Key": "Item2",
"Size": 636.66,
"Baz": "foo"
}
]
}
}
I need to find the average size of each items from all the documents in the collection. How do I do that?
Expected output:
Item1: 346.12
Item2: 563.58
I have tried the following:
db.Resources.mapReduce(
function() {
this.PItems.Workspaces.forEach(
function(z) {
emit(z.Key, z.Size);
}
);
},
function(item, space) {
var total = 0;
for ( var i=0; i<space.length; i++ )
total += size[i];
return { avg : total/space.length };
},
out: { inline: 1 }
);
I am getting a syntax error: SyntaxError: missing ) after argument list. What am I missing here?
mongodb mapreduce
asked Jan 3 at 9:47
NemoNemo
8,04983355
|
show 3 more comments
3
My document is of format:
{
"PItems": {
"Workspaces": [
{
"Key": "Item1",
"Size": 228.399,
"Foo": "bar"
},
{
"Key": "Item2",
"Size": 111.399,
"Bar": "baz"
},
{
"Key": "Item2",
"Size": 636.66,
"Baz": "foo"
}
]
}
}
I need to find the average size of each items from all the documents in the collection. How do I do that?
Expected output:
Item1: 346.12
Item2: 563.58
I have tried the following:
db.Resources.mapReduce(
function() {
this.PItems.Workspaces.forEach(
function(z) {
emit(z.Key, z.Size);
}
);
},
function(item, space) {
var total = 0;
for ( var i=0; i<space.length; i++ )
total += size[i];
return { avg : total/space.length };
},
out: { inline: 1 }
);
I am getting a syntax error: SyntaxError: missing ) after argument list. What am I missing here?
mongodb mapreduce
asked Jan 3 at 9:47
NemoNemo
8,04983355
Why mapreduce not aggregation? As aggregation is much faster then the mapreduce
– Anthony Winzlet
Jan 3 at 9:53
Edited the example. In my case item can repeat in a document. How can I do it using aggregation?
– Nemo
Jan 3 at 9:56
Could you post the expected output as well
– Anthony Winzlet
Jan 3 at 9:58
Edited with expected output
– Nemo
Jan 3 at 10:03
1
My be you are looking for something like thisdb.collection.aggregate([ { $unwind: "$PItems.Workspaces" }, { $group: { _id: "$PItems.Workspaces.Key", average: { $avg: "$PItems.Workspaces.Size" } } } ])mongoplayground.net/p/isr2COOVTjF
– Anthony Winzlet
Jan 3 at 10:25
|
show 3 more comments
3
3
3
1
My document is of format:
{
"PItems": {
"Workspaces": [
{
"Key": "Item1",
"Size": 228.399,
"Foo": "bar"
},
{
"Key": "Item2",
"Size": 111.399,
"Bar": "baz"
},
{
"Key": "Item2",
"Size": 636.66,
"Baz": "foo"
}
]
}
}
I need to find the average size of each items from all the documents in the collection. How do I do that?
Expected output:
Item1: 346.12
Item2: 563.58
I have tried the following:
db.Resources.mapReduce(
function() {
this.PItems.Workspaces.forEach(
function(z) {
emit(z.Key, z.Size);
}
);
},
function(item, space) {
var total = 0;
for ( var i=0; i<space.length; i++ )
total += size[i];
return { avg : total/space.length };
},
out: { inline: 1 }
);
I am getting a syntax error: SyntaxError: missing ) after argument list. What am I missing here?
mongodb mapreduce
asked Jan 3 at 9:47
NemoNemo
8,04983355
My document is of format:
{
"PItems": {
"Workspaces": [
{
"Key": "Item1",
"Size": 228.399,
"Foo": "bar"
},
{
"Key": "Item2",
"Size": 111.399,
"Bar": "baz"
},
{
"Key": "Item2",
"Size": 636.66,
"Baz": "foo"
}
]
}
}
I need to find the average size of each items from all the documents in the collection. How do I do that?
Expected output:
Item1: 346.12
Item2: 563.58
I have tried the following:
db.Resources.mapReduce(
function() {
this.PItems.Workspaces.forEach(
function(z) {
emit(z.Key, z.Size);
}
);
},
function(item, space) {
var total = 0;
for ( var i=0; i<space.length; i++ )
total += size[i];
return { avg : total/space.length };
},
out: { inline: 1 }
);
I am getting a syntax error: SyntaxError: missing ) after argument list. What am I missing here?
mongodb mapreduce
mongodb mapreduce
asked Jan 3 at 9:47
NemoNemo
8,04983355
asked Jan 3 at 9:47
NemoNemo
8,04983355
edited Jan 3 at 9:59
Nemo
asked Jan 3 at 9:47
NemoNemo
8,04983355
asked Jan 3 at 9:47
NemoNemo
8,04983355
asked Jan 3 at 9:47
NemoNemo
8,04983355
8,04983355
Why mapreduce not aggregation? As aggregation is much faster then the mapreduce
– Anthony Winzlet
Jan 3 at 9:53
Edited the example. In my case item can repeat in a document. How can I do it using aggregation?
– Nemo
Jan 3 at 9:56
Could you post the expected output as well
– Anthony Winzlet
Jan 3 at 9:58
Edited with expected output
– Nemo
Jan 3 at 10:03
1
My be you are looking for something like thisdb.collection.aggregate([ { $unwind: "$PItems.Workspaces" }, { $group: { _id: "$PItems.Workspaces.Key", average: { $avg: "$PItems.Workspaces.Size" } } } ])mongoplayground.net/p/isr2COOVTjF
– Anthony Winzlet
Jan 3 at 10:25
|
show 3 more comments
Why mapreduce not aggregation? As aggregation is much faster then the mapreduce
– Anthony Winzlet
Jan 3 at 9:53
Edited the example. In my case item can repeat in a document. How can I do it using aggregation?
– Nemo
Jan 3 at 9:56
Could you post the expected output as well
– Anthony Winzlet
Jan 3 at 9:58
Edited with expected output
– Nemo
Jan 3 at 10:03
1
My be you are looking for something like thisdb.collection.aggregate([ { $unwind: "$PItems.Workspaces" }, { $group: { _id: "$PItems.Workspaces.Key", average: { $avg: "$PItems.Workspaces.Size" } } } ])mongoplayground.net/p/isr2COOVTjF
– Anthony Winzlet
Jan 3 at 10:25
Why mapreduce not aggregation? As aggregation is much faster then the mapreduce
– Anthony Winzlet
Jan 3 at 9:53
Why mapreduce not aggregation? As aggregation is much faster then the mapreduce
– Anthony Winzlet
Jan 3 at 9:53
Edited the example. In my case item can repeat in a document. How can I do it using aggregation?
– Nemo
Jan 3 at 9:56
Edited the example. In my case item can repeat in a document. How can I do it using aggregation?
– Nemo
Jan 3 at 9:56
Could you post the expected output as well
– Anthony Winzlet
Jan 3 at 9:58
Could you post the expected output as well
– Anthony Winzlet
Jan 3 at 9:58
Edited with expected output
– Nemo
Jan 3 at 10:03
Edited with expected output
– Nemo
Jan 3 at 10:03
1
1
My be you are looking for something like this
db.collection.aggregate([ { $unwind: "$PItems.Workspaces" }, { $group: { _id: "$PItems.Workspaces.Key", average: { $avg: "$PItems.Workspaces.Size" } } } ]) mongoplayground.net/p/isr2COOVTjF– Anthony Winzlet
Jan 3 at 10:25
My be you are looking for something like this
db.collection.aggregate([ { $unwind: "$PItems.Workspaces" }, { $group: { _id: "$PItems.Workspaces.Key", average: { $avg: "$PItems.Workspaces.Size" } } } ]) mongoplayground.net/p/isr2COOVTjF– Anthony Winzlet
Jan 3 at 10:25
|
show 3 more comments
1 Answer
1
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oldest
votes
0
You can use below aggregation
db.collection.aggregate([
{ "$unwind": "$PItems.Workspaces" },
{ "$group": {
"_id": "$PItems.Workspaces.Key",
"average": { "$avg": "$PItems.Workspaces.Size" }
}}
])
answered Jan 4 at 3:17
Anthony WinzletAnthony Winzlet
18.4k42346
add a comment |
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1 Answer
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1 Answer
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0
You can use below aggregation
db.collection.aggregate([
{ "$unwind": "$PItems.Workspaces" },
{ "$group": {
"_id": "$PItems.Workspaces.Key",
"average": { "$avg": "$PItems.Workspaces.Size" }
}}
])
answered Jan 4 at 3:17
Anthony WinzletAnthony Winzlet
18.4k42346
add a comment |
0
You can use below aggregation
db.collection.aggregate([
{ "$unwind": "$PItems.Workspaces" },
{ "$group": {
"_id": "$PItems.Workspaces.Key",
"average": { "$avg": "$PItems.Workspaces.Size" }
}}
])
answered Jan 4 at 3:17
Anthony WinzletAnthony Winzlet
18.4k42346
add a comment |
0
0
0
You can use below aggregation
db.collection.aggregate([
{ "$unwind": "$PItems.Workspaces" },
{ "$group": {
"_id": "$PItems.Workspaces.Key",
"average": { "$avg": "$PItems.Workspaces.Size" }
}}
])
answered Jan 4 at 3:17
Anthony WinzletAnthony Winzlet
18.4k42346
You can use below aggregation
db.collection.aggregate([
{ "$unwind": "$PItems.Workspaces" },
{ "$group": {
"_id": "$PItems.Workspaces.Key",
"average": { "$avg": "$PItems.Workspaces.Size" }
}}
])
answered Jan 4 at 3:17
Anthony WinzletAnthony Winzlet
18.4k42346
answered Jan 4 at 3:17
Anthony WinzletAnthony Winzlet
18.4k42346
answered Jan 4 at 3:17
Anthony WinzletAnthony Winzlet
18.4k42346
answered Jan 4 at 3:17
Anthony WinzletAnthony Winzlet
18.4k42346
18.4k42346
add a comment |
add a comment |
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Why mapreduce not aggregation? As aggregation is much faster then the mapreduce
– Anthony Winzlet
Jan 3 at 9:53
Edited the example. In my case item can repeat in a document. How can I do it using aggregation?
– Nemo
Jan 3 at 9:56
Could you post the expected output as well
– Anthony Winzlet
Jan 3 at 9:58
Edited with expected output
– Nemo
Jan 3 at 10:03
1
My be you are looking for something like this
db.collection.aggregate([ { $unwind: "$PItems.Workspaces" }, { $group: { _id: "$PItems.Workspaces.Key", average: { $avg: "$PItems.Workspaces.Size" } } } ])mongoplayground.net/p/isr2COOVTjF– Anthony Winzlet
Jan 3 at 10:25