user971956 - 2 months ago 8

Groovy Question

I have two maps in Groovy

`[a: 1, b: 2]`

`[b:1, c:3]`

`[a: 1, b: 3, c: 3]`

Thanks

Answer

Yet another solution would be:

```
def m1 = [ a:1, b:2 ]
def m2 = [ b:1, c:3 ]
def newMap = [m1,m2]*.keySet().flatten().unique().collectEntries {
[ (it): [m1,m2]*.get( it ).findAll().sum() ]
}
```

Taking epidemian's answer as inspiriation, you can also write a method to handle multiple maps

```
def m1 = [a: 1, b: 2]
def m2 = [b: 1, c: 3]
def combine( Map... m ) {
m.collectMany { it.entrySet() }.inject( [:] ) { result, e ->
result << [ (e.key):e.value + ( result[ e.key ] ?: 0 ) ]
}
}
def newMap = combine( m1, m2 )
```

Source (Stackoverflow)

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