CSV
Standardizing Phone Numbers in a CSV File With Python
Normalize phone numbers to E.164 with a regex and the phonenumbers library; the regex accepted 43.8% more numbers than the library calls valid.
8 min read
Library
Everything you need to level up your coding skills.
YAML
Handling YAML Uploads From Users Without Getting Burned
A 40-line guard for accepting YAML uploads: size cap, UTF-8, safe parsing, expanded-size and depth limits, then key checks. Ten test inputs and what each did.
7 min read
CSV
Handling Missing Values in a CSV File Without Guessing
A CSV has no NULL, so missing arrives as empty, a dash, N/A or null. Inventory the tokens, convert to real NA, keep the reason and see what fillna(0) does.
8 min read
JSON
Choosing Between a JSON Column and a Document Database
When a JSON column in PostgreSQL, MySQL or SQLite is enough, and when a document database such as MongoDB earns its place, with measured numbers.
8 min read
Excel
Checking an Excel Upload Before Reading It Into Code
Check an Excel upload before parsing: size, name, zip signature, required parts, macro parts, sheet names and header row, in a fixed order with clear errors.
7 min read
XML
Using XML Namespaces for Extensions Without the Chaos
Let partners add their own data to your XML format safely by giving each extension its own namespace, with a reader that ignores what it does not own.
6 min read
PostgreSQL
Why the Planner Estimates the Wrong Number of Rows
Why the PostgreSQL planner estimates the wrong number of rows: stale statistics, skew, correlated columns, expressions and parameters, with the fix for each.
7 min read
CSV
Turning Currency Strings Into Numbers in a CSV Exactly
Parse $1,234.50, (12.50), 1.234,50 € and 7,00 into exact Decimals, find the cases where stripping symbols is wrong, and spot a column that mixes currencies.
8 min read
Excel
Password Protected Excel Files and Scripts That Read Them
Read password protected Excel files from a script with msoffcrypto-tool, tell file encryption from sheet protection, and keep passwords out of code and logs.
7 min read
CSV
Fixing Mixed Date Formats in a CSV Column Without Guessing
Four formats in one date column, 959 values that are not dates and 15,642 that could be read two ways. Parse with explicit formats and report what you cannot.
9 min read
XML
Mixed Content in XML and Why It Hurts Parsing and Mapping
Text and elements side by side look natural in documents and break data models. How ElementTree and lxml expose text and tail, and what to do instead.
6 min read
YAML
Secrets Accidentally Committed in YAML Files and the Cleanup
What to do when a token lands in a values or config YAML: removing it from the file leaves it in history, gitleaks finds it, and rotation is the real fix.
6 min read
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