---
name: catAttrs
args: [attr, list]
---
Collect each attribute named *attr* from a list of attribute
sets.  Attrsets that don't contain the named attribute are
ignored. For example,

```nix
builtins.catAttrs "a" [{a = 1;} {b = 0;} {a = 2;}]
```

evaluates to `[1 2]`.
