AI glossary: terms starting with F

A string with f before the quote; each {expression} inside it is replaced by its value: f"The {item} costs {price}".

the derivative of f, a function of x

Example: x² → 2x

Probability of a positive flag when the class is real: 10% in the construction.

Selection by integer positions; returns a copy

A recorded property of a message, such as whether a certain word appears in it.

A stored numeric value standing for a documented category or status.

The table of features, one row per sample, written X.

one axis per feature

Example: white-cell count against temperature

One attribute a dataclass lists, with a type hint: rating: int.

What open gives back; you read from it or write to it. with closes it.

A condition that determines which items are included.

Reduction in sampling spread when draws use a substantial fraction of a finite frame: √((N − n) / (N − 1)).

The method that learns from examples. It stores what it learned in attributes ending in _, and returns self.

Prediction from the estimated line.

Variation from resampled validation rows while fitted models stay unchanged.

An observed value outside a declared box-plot fence. It is a flag for inspection, not a proven error.

A number with a decimal point: 24.75, 2.0.

a sign, a significand and an exponent, ±1.f × 2ᵉ

Example: 0.75 = 1.1₂ × 2⁻¹

//: divides, then rounds down toward negative infinity. 10 // 3 is 3, and -7 // 2 is -4.

One of the k parts.

After the colon in an "f" string's braces, how a value is shown: {price:.2f}, {52000:,}, {name:<10}.

A tool that rewrites code's layout, without changing what it does: ruff format.

compute each node's value from its inputs, in order

Example: 3, 5, 25

The execution state for one call, including its local namespace and current instruction; its active call-stack entry ends when the call returns.

The number of observations in a bin.

Bin count divided by bin width, used when histogram bins have unequal widths.

A dataclass that blocks field assignment and deletion, @dataclass(frozen=True). Nested mutable values can still change. With the default equality, its generated hash works only when every hashed field is hashable.

An immutable, hashable set: frozenset({1, 2}).

A named piece of code that does one job. print's job is to display a value.

A def statement; running it creates a function object and binds its name. The body does not run until a call.

An object created by a function definition or lambda, which can be passed, stored and called.

the area's rate of growth is the curve's height

Example: A′(x) = x²