General

Python

Groovy

repr(x)
x.inspect(), x.dump()
x.y if x else None
x?.y
"%(foo)s" % locals()
"${foo}"

Lists

Python

Groovy

not x
!x
x.empty
len(x)
x.size()
for item, idx in enumerate(x): ...
x.eachWithIndex { item, idx -> ... }

Maps

Python

Groovy

{}
[:] // an empty map
Depends:
d if used like:  for k in d:
list(d) if list needed
d[iter].keys() explicitly
d.keySet()
d.[iter]values()
d.values()
[k+1 for k in d]
d.collect { k, v -> k+1 }
d = dict(zip(k, v))
k = 1..3
v = 'a'..'c'
d = [:]; k.eachWithIndex { it, i -> d[it] = v[i] }
println d // [1:"a", 2:"b", 3:"c"]

Ranges/Slices

Python

Groovy

range(3)
0..<3
range(1, 3+1)
1..3
range(0, 10, 2)

not represented as a data type but you can use

0.step(10, 2) {...}
"abcdef"[3:]
"abcdef"[3..-1]

Object access

Python

Groovy

m = 'strip'; getattr(' ! ', m)()
m = 'trim'; ' ! '."$m"()
args = ('a', 2); 'abcabc'.find(*args)
args = ['a', 2]; 'abcabc'.indexOf(*args)