Logo
Overview

Web Scraping

July 25, 2024
3 min read

Weekly Macro Update Automation — One-Pager

Key Libraries

Web automation & scraping

  • selenium — browser automation, DOM navigation, waiting for dynamic elements, XPath extraction, and interaction with site consent banners, as implemented in Scraping_Calendar_Economics.py.
  • selenium.webdriver.support (EC, WebDriverWait) — synchronization for dynamic page loads and element visibility.
  • selenium.common.exceptions — robust handling of timeouts, missing elements, and blocked interactions.

Data manipulation & cleaning

  • pandas — central library for reading the input indicator list, building and filtering DataFrames, column transformations, and exporting final data.
  • re — regex matching to identify relevant indicators in scraped text and aggressive text cleaning before export.

File output & Excel integration

  • openpyxl — Excel writing through ExcelWriter, creating the final structured output file.

Problem

➡️ Manual collection of macroeconomic data was inefficient

  • Weekly internal macro updates (PMIs, CPIs, labor data, sentiment indices, etc.) were compiled manually from free online sources.
  • The indicators were predefined and recurring, forcing analysts to repeat the same tasks every week.

➡️ Non-automated consolidation process

  • Each indicator had to be searched manually, copied, and formatted into the internal reporting template.
  • Ensuring that all predefined indicators were included was time-consuming and prone to human error.

➡️ Need for an internal weekly report

  • The final dataset had to be compiled and distributed internally, requiring precision, consistency, and stability.

To sum up:

  • Manual and repetitive searches → high weekly operational burden.
  • No automation → risk of missing indicators or formatting inconsistencies.
  • Recurring predefined dataset → ideal candidate for automation.

Solution Overview

➡️ Automated Web Scraping via Selenium

  • Developed a Selenium workflow that navigates public economic calendars, applies filters, and extracts relevant macro indicators.
  • Scraped values are parsed into pandas DataFrames and validated through custom filtering logic.

➡️ Input-driven and scalable architecture

  • The process is fully governed by a single input Excel file listing:
    • the indicator name
    • the geographic area
    • the source website
  • Adding/removing indicators requires no modification to the code — only adjustments to the input list.

➡️ Excel Output for Internal Weekly Reporting

  • The consolidated dataset is automatically exported to an Excel file, with one row per indicator and enriched metadata (translation, category, documentation links).
  • Values are then placed into a fixed internal template for weekly circulation

Results

  • Operational efficiency: reduced weekly extraction time from ~1 hour to ~15 minutes (only final formatting checks remain).
  • Accuracy & consistency: fixed indicator list ensures completeness and standardization.
  • Reliability: scraping logic filters out stale data and captures only newly published indicators.
  • Quality of internal reporting: faster turnaround and structurally consistent weekly macro updates.

Challenges Encountered

  • Irregular publication schedules

    • Many indicators are not released weekly.
    • Selenium applies date filters available on the website; if no new release exists, the script skips the indicator to avoid importing stale data.
  • Heterogeneous website structures

    • Economic calendars use different HTML structures, requiring custom XPath logic and dynamic waits for each source.
  • Matching accuracy

    • Some indicators have similar names (“inflation”, “core inflation”, “MoM inflation”), requiring increasingly strict matching rules in the filtering logic.
  • Resilience of scraping

    • Cookie banners, page delays, or blocked buttons required exception handling and fallback logic.

Possible Improvements

Full automation of the internal report
Generate a final ready-to-send weekly PDF or formatted Excel without manual adjustments.

Alerting & monitoring
Notify the team when:

  • an indicator is missing
  • a site layout changes
  • scraping returns unexpected values

Migration to API sources
Replace scraping with free APIs (when available) to increase reliability and reduce runtime.