04-03: City Statistics — Matplotlib Bar Charts

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Produces a 2×2 subplot figure showing Bangladesh city statistics: population (vertical bar), area (horizontal bar), population density (colour-coded), and literacy rate (with a reference line). Saved as city_statistics.png.

Topics covered: plt.subplots() · ax.bar() · ax.barh() · ax.text() (annotations) · ax.axvline() · colour maps · plt.tight_layout() · plt.savefig()

Difficulty: ⭐⭐ Intermediate

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Requirements

pip install matplotlib numpy

How to Run

python main.py

Output: city_statistics.png

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Key Concepts Practised

Concept	Where used
plt.subplots(2, 2)	2×2 grid layout
ax.bar() / ax.barh()	Vertical / horizontal bars
ax.text() on bars	Data labels
plt.cm.Blues(linspace)	Colour gradient
Conditional colours	Red if density > 40k
ax.axvline()	Reference line at 60%
plt.savefig(dpi=150)	Export to PNG