Educational Cards
Learn from video content, text, and interactive tasks
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Creating, slicing, and selecting arrays
Everything you did with lists and nested loops now collapses into one fast, typed object: the NumPy...
Measurement scales and your first function
Everything read from a CSV is a string, so before you can compute you must parse each value into...
DataFrames: reading, filtering, adding columns
pandas unifies everything so far into one object: the DataFrame , a table with named columns and a...
groupby, merge, and counting carefully
The workhorse is groupby — the "split by key, then reduce" sentence from the aggregation topic, now...
Handling missing data and validating input
In pandas the everyday moves are to detect, then deliberately decide: python...
Confusion matrix, precision, and recall
A model is only as trustworthy as your ability to judge it. Every prediction falls into one of four...
Entropy as average information per symbol
Entropy is the average information per symbol for a distribution. For probabilities p_i, H = sum_i...
Information as negative log probability
Perfect compression linked an n-bit codeword to probability 2^-n, so n = -log_2 p for that message...
Perfect compression looks like random noise
True random noise is incompressible: each bit is a fair coin flip, independent of the rest. An...
Information of language
English letter frequencies are wildly skewed; assuming twenty-six equally likely letters wastes...
Compression limits and the intelligence slogan
Text can always be encoded more compactly than fixed-width ASCII: frequent symbols deserve shorter...
Robot warmup: skewed symbols and prefix codes
A robot on a distant moon sends movement instructions drawn from a small, skewed alphabet. Three...