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---
title: Using a YAML object of a parsed mapping
---
When a YAML document with mappings is parsed, it is not parsed
as a dict but as a YAML object which behaves very similarly to
a dict, but with some extra capabilities.
You can use .items(), .keys(), .values(), look up items with
square bracket notation, .get(key, with_default_if_nonexistent)
and use "x in y" notation to determine key membership.
To retrieve the equivalent dict (containing just other dicts, lists
and strings/ints/etc.) use .data.
Example yaml_snippet:
```yaml
a: 1
b: 2
c: 3
```
```python
from strictyaml import Map, Int, load
from ensure import Ensure
schema = Map({"a": Int(), "b": Int(), "c": Int()})
```
.is_mapping():
```python
Ensure(load(yaml_snippet, schema).is_mapping()).is_true()
```
Equivalence with equivalent plain dict:
```python
Ensure(load(yaml_snippet, schema)).equals({"a": 1, "b": 2, "c": 3})
```
.items():
```python
Ensure(load(yaml_snippet, schema).items()).equals([("a", 1), ("b", 2), ("c", 3)])
```
Use in to detect presence of a key:
```python
Ensure("a" in load(yaml_snippet, schema)).is_true()
```
.values():
```python
Ensure(load(yaml_snippet, schema).values()).equals([1, 2, 3])
```
.keys():
```python
Ensure(load(yaml_snippet, schema).keys()).equals(["a", "b", "c"])
```
Key lookup:
```python
yaml = load(yaml_snippet, schema)
Ensure(yaml[yaml.keys()[0]]).equals(1)
```
Dict lookup:
```python
Ensure(load(yaml_snippet, schema)["a"]).equals(1)
```
.get():
```python
Ensure(load(yaml_snippet, schema).get("a")).equals(1)
```
.get() nonexistent:
```python
Ensure(load(yaml_snippet, schema).get("nonexistent")).equals(None)
```
len():
```python
Ensure(len(load(yaml_snippet, schema))).equals(3)
```
!!! note "Executable specification"
Documentation automatically generated from
<a href="https://github.com/crdoconnor/strictyaml/blob/master/hitch/story/mapping-representation.story">mapping-representation.story
storytests.
|
