JavaScript多数组元素删除、Ruby指定值数组元素删除方法问询

1. Removing Multiple Elements from a JavaScript Array #

There are a few solid approaches depending on whether you want to keep the original array intact (immutable) or modify it directly (mutable):

Immutable Approach (Recommended for Most Cases) #

Use filter() to create a new array excluding the elements you don't want. This avoids side effects and is easier to reason about:

const originalArray = [1, 2, 3, 4, 5];
const elementsToRemove = new Set([2, 5]); // Using Set for faster lookups
const filteredArray = originalArray.filter(item => !elementsToRemove.has(item));

// Result: filteredArray = [1, 3, 4], originalArray stays the same

Mutable Approach (Modify Original Array) #

If you need to change the original array, use splice()—but iterate backwards to avoid skipping elements (since splice shifts indices):

const arr = [1, 2, 3, 4, 5];
const elementsToRemove = [2, 5];

for (let i = arr.length - 1; i >= 0; i--) {
  if (elementsToRemove.includes(arr[i])) {
    arr.splice(i, 1); // Remove 1 element at index i
  }
}

// Result: arr = [1, 3, 4]

Another immutable option is reduce(), which builds a new array incrementally:

const original = [1, 2, 3, 4, 5];
const exclude = new Set([2, 5]);
const newArray = original.reduce((acc, curr) => {
  if (!exclude.has(curr)) acc.push(curr);
  return acc;
}, []);

2. Removing Elements from Arrays in Ruby #

Let's break this down into your two specific scenarios:

Scenario 1: Remove Specified Values from a Numeric Array #

For your array [2,4,6,3,8]:

• To remove all occurrences of a single value, use delete():

  nums = [2,4,6,3,8]
  nums.delete(6) # Removes all 6s, nums becomes [2,4,3,8]
  

• To remove multiple specified values, use reject (returns a new array) or delete_if (modifies the original):

  nums = [2,4,6,3,8]
  values_to_remove = [6, 3]
  
  # New array (original remains unchanged)
  filtered_nums = nums.reject { |num| values_to_remove.include?(num) }
  
  # Modify original array directly
  nums.delete_if { |num| values_to_remove.include?(num) }
  # Result: nums = [2,4,8]
  

Scenario 2: Remove a Specific Hash from an Array of Hashes #

For your hash array [{x: "69", y: "104"},{x: "69", y: "109"},{x: "69", y: "300"}], to delete the hash where x == "69" and y == "109":

Use reject (new array) or delete_if (mutate original):

hash_array = [{x: "69", y: "104"}, {x: "69", y: "109"}, {x: "69", y: "300"}]

# Get a new filtered array
filtered_hashes = hash_array.reject { |h| h[:x] == "69" && h[:y] == "109" }

# Or modify the original array
hash_array.delete_if { |h| h[:x] == "69" && h[:y] == "109" }

# Result in both cases: [{x: "69", y: "104"}, {x: "69", y: "300"}]

内容的提问来源于stack exchange，提问作者Frans Suny