Tag

python

134 posts

YAML

Reading YAML Front Matter From Markdown Files in Python

Split a Markdown file into YAML metadata and body with one regex, then handle dates, CRLF, a BOM, a missing closing line and body text with dashes.

6 min read

YAML

Merging Two YAML Files in Python With a Deep Merge

dict update is shallow and replaces whole blocks. A 10-line deep merge, the list policy choice and what null means, tested on a base and an override file.

6 min read

YAML

Validating YAML Configuration With pydantic Models

Load YAML, validate it with pydantic models and get every error with its path. The Norway problem caught, extra keys rejected and ranges enforced.

7 min read

YAML

Loading Multiple Documents From One YAML File in Python

A YAML file can hold several documents separated by three dashes. safe_load fails on them, safe_load_all reads them and safe_dump_all writes them.

6 min read

YAML

Preserving Comments and Order With ruamel yaml Round Trips

Edit a YAML file from Python and keep its comments, key order, quotes and block strings with ruamel.yaml round-trip mode, plus settings and caveats.

7 min read

XML

Reading Publisher Metadata in JATS XML for One Article

Pull the title with inline markup, authors with ORCID and affiliations, group authors, editors and the several dates out of one JATS article front matter.

7 min read

XML

Using DuckDB to Read XML Through Python and Arrow Tables

Stream XML into Arrow batches with lxml, query them in DuckDB at once, or try the community webbed extension. 1.2 million lines in 7.9 s with a 53 ms query.

6 min read

JSON

Parsing a Package Registry Metadata File Where Keys Are Data

Read a package metadata document where version numbers are keys: json_each, DuckDB MAP inference, semver sorting, dist-tags versus max, and the time map.

7 min read

JSON

Converting YAML to JSON for Tools That Need It Safely

Convert YAML to JSON with PyYAML and ruamel.yaml, and handle dates, yes and no, octal numbers, non-string keys, anchors, multiple documents and floats.

8 min read

CSV

An Ecommerce Export With Commas Inside Product Names

A product export writes names with commas and no quotes, so rows have 6 fields, not 4. Rejoin the middle fields from the good ends and verify every row.

6 min read

YAML

Writing YAML From Python Without Ugly Output or Surprises

PyYAML safe_dump sorts keys, escapes Unicode and quotes multiline strings with blank lines. The options and a block-string representer that fix each default.

6 min read

YAML

Loading YAML in Python With PyYAML safe_load Explained

What yaml.safe_load returns, how to open files correctly, why the C loader is six times faster and the type surprises that come with PyYAML.

6 min read