Python · Theory

Generators in Python

Theory

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Generators in Python

A generator produces values one at a time with yield. def gen(): yield 1; yield 2. for x in gen(): prints 1 then 2. It does not build a full list in memory. Generator expression: (x * x for x in range(10)) — parentheses, not brackets. yield pauses. return ends.

Contrast with list comprehension: [...] builds everything now. Generator is lazy. That memory sentence is why interviews ask. next(g) also pulls one value.

Generators in Python — output — [1, 2, 3]. yield pauses and continues — not all at once like return.

Exam tip

yield vs return in one contrast.

Example

# Generator
def count():
    yield 1
    yield 2
    yield 3

print(list(count()))

Generators in Python — output: [1, 2, 3]. yield pauses and continues — not all at once like return.

Short notes

Defyield values, lazy.
Rulefor consumes the generator.
Diff≠ list comprehension.

Python · Theory

Generators in Python

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Theory

86/268

Generators in Python

Contrast with list comprehension: [...] builds everything now. Generator is lazy. That memory sentence is why interviews ask. next(g) also pulls one value.

Generators in Python — output — [1, 2, 3]. yield pauses and continues — not all at once like return.

Exam tip

yield vs return in one contrast.

Example

# Generator
def count():
    yield 1
    yield 2
    yield 3

print(list(count()))

Generators in Python — output: [1, 2, 3]. yield pauses and continues — not all at once like return.

Short notes

Defyield values, lazy.
Rulefor consumes the generator.
Diff≠ list comprehension.

Generators in Python

Example

Short notes

Questions

Generators in Python

Example

Short notes

Questions