LowFile-scopeJava Plug & play

Combine Multiple Loops Over the Same Collection

Ensure that multiple loops over the same collection are combined into a single loop to improve efficiency.

Why this matters

Iterating over the same collection multiple times in separate loops is inefficient. Combining them reduces execution time and improves performance.

Bad vs. good

Side-by-side examples engineers can pattern-match during review.

Avoid

public void doSomethingToAList(List<String> strings) {
  for (String str : strings) {
    doStep1(str);
  }
  for (String str : strings) {  // Noncompliant
    doStep2(str);
  }
}

Prefer

public void doSomethingToAList(List<String> strings) {
  for (String str : strings) {
    doStep1(str);
    doStep2(str);
  }
}

More snippets

Bad

public void doSomethingToAList(List<String> strings) {
  for (String str : strings) {
    doStep1(str);
  }
  for (String str : strings) {  // Noncompliant
    doStep2(str);
  }
}

Good

public void doSomethingToAList(List<String> strings) {
  for (String str : strings) {
    doStep1(str);
    doStep2(str);
  }
}

Related rules

From the same buckets as this rule.

Critical
Avoid Duplicating String Literals
Store repeated string literals in constants or variables to improve maintainability and reduce redundancy.
duplication-complexitymaintainability
Critical
Avoid Redundant `None` Comparisons
Identify cases where `x is None` or `x is not None` is used redundantly when `x` is always or never `None`. This may indicate a deeper logic issue.
duplication-complexityreadability-refactor+1
High
Avoid Functions That Always Return the Same Value
Identify functions that return the same value regardless of input. This may indicate poor design or a logic error.
duplication-complexityreadability-refactor+1

Why this matters

Bad vs. good

More snippets

Related rules

Avoid Duplicating String Literals

Avoid Redundant `None` Comparisons

Avoid Functions That Always Return the Same Value

Why this matters

Bad vs. good

More snippets

Related rules

Avoid Duplicating String Literals

Avoid Redundant `None` Comparisons

Avoid Functions That Always Return the Same Value