[x for x in range(20) if x%2==0 and x%5==0]
Iteration Patterns

Meaning

Producescription: "Produces a list of integers from 0 to 19 that are divisible by both 2 and 5 (i.e., multiples of 10).", "primary_function":"Filter a range of integers using a conjunction of two modulo conditions within a list comprehension." ,"communicative_purpose":"Express a concise filter for numbers meeting multiple criteria." ,"trigger_situations":"When needing to select numbers satisfying multiple modulus conditions from a range or iterable." ,"contexts":"Data filtering, numeric processing, interview coding exercises, teaching list comprehensions." ,"output_priority":"medium" ,"frequency":"common" ,"formulaicity":"high" ,"construction_type":"list comprehension" ,"acquisition_priority":"intermediate" ,"pattern":"[x for x in iterable if condition1 and condition2]" ,"core_structure":"[ expression for item in iterable if condition ]" ,"substitution_slots":"expression: x ; iterable: range(20) ; condition: x%2==0 and x%5==0" ,"typical_collocates":"range, for, in, if, and, %, ==" ,"common_substitutions":"replace range(20) with other iterables; change conditions to other predicates; replace expression with a function call or transformation." ,"variations":"use 'or' instead of 'and'; change modulo divisor; apply a transformation like x*2; use filter() or a generator expression." ,"common_mistakes":"using bitwise '&' instead of 'and'; misplacing parentheses; forgetting to close brackets; confusing modulo precedence." ,"similar_contrasting":"Similar: [x for x in range(20) if x%10==0]; Contrast: filter(lambda x: x%2==0 and x%5==0, range(20)) or an explicit for‑loop with append." ,"interference_warnings":"Confusing bitwise '&' with logical 'and'; assuming modulo has lower precedence than 'and'; omitting the second condition." ,"nuance":"Both conditions must be true; due to short‑circuit evaluation the second condition is skipped if the first is false; 0 is included because 0 % n == 0 for any n." ,"pragmatic_effect":"Concisely communicates a multi‑condition filter, signalling the intent to select numbers that satisfy all given criteria." ,"note":"Includes 0 because 0 % n == 0 for any n." ,"recall_cue":"Numbers divisible by both 2 and 5 up to 20." ,"spacing_tag":"medium" ,"upgrade_path":"Consider using filter() with a lambda or itertools.filterfalse for reusable predicates, or a single combined condition (x%10==0) for simplicity." ,"chunk_family":"list comprehension filters" ,"register":"technical" ,"type_label":"list comprehension pattern" ,"semantic_transparency":"transparent" ,"discourse_function":"referential"} {

Primary Function

Data transformation

Communicative Purpose

Filters numbers that are multiples of both 2 and 5 from a range.

Pattern

[result for item in iterable if condition1 and condition2]

Core Structure

[ ... for ... in ... if ... ]

Função primária

Data transformation

Propósito comunicativo

Filters numbers that are multiples of both 2 and 5 from a range.

Situações de gatilho

Data analysis: extracting numbers that are even and divisible by 5 from a dataset; Interview coding: generating a list of integers that satisfy multiple modulo conditions.

Contextos

Python scripts, data‑processing pipelines, teaching materials for introductory programming.

Padrão

[result for item in iterable if condition1 and condition2]

Estrutura central

[ ... for ... in ... if ... ]

Slots de substituição

result: expression producing each list element, item: element variable from iterable, iterable: any iterable collection, condition1: first boolean predicate, condition2: second boolean predicate

Colocados típicos

  • range
  • if
  • and
  • %
  • ==
  • for
  • in
  • list comprehension

Substituições comuns

  • replace the iterable with any other iterable
  • change 'and' to 'or' for alternative logic
  • use a function call in the result position
  • combine conditions into a single expression such as x%10==0

Erros comuns

using bitwise '&' instead of logical 'and' → SyntaxError or wrong logic; misplacing parentheses causing the condition to apply to the wrong part → unexpected elements in the result; forgetting to close the brackets → SyntaxError; assuming modulo has lower precedence than 'and' → logical error

Similar / contraste

Similar: [x for x in range(20) if x%10==0]; Contrast: filter(lambda x: x%2==0 and x%5==0, range(20)) which returns an iterator instead of a list

Interferências

Coming from C: using && instead of 'and' will cause a syntax error in Python; Coming from JavaScript: assuming && short‑circuits the same way but forgetting Python's 'and' precedence can lead to unexpected results.

Família do chunk

  • list comprehension filters
  • conditional list comprehensions
  • generator expressions

Nuance

Do not use this pattern when the dataset is huge and memory consumption matters; list comprehensions build the entire list in memory, which may be slower than a generator expression; the conditions are evaluated left‑to‑right, so the second condition is skipped for items failing the first.

Efeito pragmático

Provides a concise, readable way to filter sequences with multiple criteria, reducing boilerplate loops and making intent explicit.

Dica de memória

Think of a sieve that only lets through numbers that pass both the even and the five‑multiple holes.

Nota

Includes 0 because 0 % n == 0 for any n, so 0 appears in the result when the range starts at 0.

Upgrade path

Use a generator expression for lazy evaluation or employ itertools.filterfalse for more complex predicates.

Frequência: HighFormulaicidade: Semi-fixedTipo de construção: list comprehensionPrioridade de aquisição: Active recallPrioridade de output: BothTag de espaçamento: Medium-term

Log in to save chunks.