Meaning
Creates a list of (index, value) tuples from an iterable using enumerate within a list comprehension. Useful when you need both the position and the element while building a new list.
Primary Function
Iteration and mapping
Communicative Purpose
Produces a list of index-value pairs from an iterable.
Pattern
[(index, value) for index, value in enumerate(iterable)]
Core Structure
[(..., ...) for ... , ... in enumerate(...)]
Função primária
Iteration and mapping
Propósito comunicativo
Produces a list of index-value pairs from an iterable.
Situações de gatilho
Data processing: converting a list into (index, item) pairs for CSV export; Visualization: labeling data points with their positions for plotting
Contextos
Python codebases, data processing scripts, algorithms that require indexed iteration.
Padrão
[(index, value) for index, value in enumerate(iterable)]
Estrutura central
[(..., ...) for ... , ... in enumerate(...)]
Slots de substituição
iterable: any iterable; index_var: identifier; value_var: identifier
Colocados típicos
- list
- tuple
- range
- zip
- dict construction
Substituições comuns
- list(enumerate(iterable)) produces an iterator of tuples
- using a for loop to append pairs.
Erros comuns
Confusing the order of index and value; forgetting parentheses around the tuple; using enumerate on non-iterable.
Similar / contraste
zip(range(len(iterable)), iterable) – more verbose; using a plain for loop with manual index increment.
Interferências
Coming from languages where loops start at 1 (e.g., MATLAB, R): expecting index to start at 1 unless you add 1 → index starts at 0 in Python
Família do chunk
- enumerate
- list comprehension
- zip
- map
Nuance
enumerate starts at 0 by default; you can specify a start argument. The list comprehension builds a new list; for large iterables consider using enumerate directly in a for loop to avoid extra memory.
Efeito pragmático
Makes intent explicit and avoids manual index management.
Dica de memória
Think 'enumerate gives me index and value; list comprehension packs them'.
Nota
The list comprehension builds a new list; for memory‑efficient iteration over large data, use enumerate directly in a for loop instead.
Upgrade path
Using enumerate with a start argument for 1-based indexing, or using itertools.starmap for more complex transformations.
Log in to save chunks.