如何在Ruby on Rails中合并JSON数组：按月份累加收入

To combine your JSON array by month (summing revenues and removing duplicate month entries), you can follow these straightforward steps using Ruby's built-in enumerables and Rails' JSON utilities:

Step 1: Parse the JSON into a Ruby Array #

First, convert your raw JSON string into a Ruby array of hashes so we can manipulate it:

# Your original JSON string
json_input = '[{"revenu":0,"month":"January"}, {"revenu":0,"month":"February"}, {"revenu":0,"month":"March"}, {"revenu":0,"month":"April"}, {"revenu":1832.4430203602753,"month":"May"}, {"revenu":4502.1,"month":"May"}, {"revenu":54.673303657726436,"month":"May"}, {"revenu":0,"month":"June"}, {"revenu":0,"month":"July"}, {"revenu":0,"month":"August"}, {"revenu":0,"month":"September"}, {"revenu":0,"month":"October"}, {"revenu":0,"month":"November"}, {"revenu":0,"month":"December"}]'

# Parse JSON to Ruby array
raw_data = JSON.parse(json_input)

Step 2: Group Entries by Month #

Use Ruby's group_by method to cluster all entries by their month value:

grouped_by_month = raw_data.group_by { |entry| entry["month"] }

This creates a hash where each key is a month name, and the value is an array of all entries associated with that month.

Step 3: Sum Revenue for Each Month #

Iterate over each grouped month, calculate the total revenue, and build your merged dataset:

merged_data = grouped_by_month.map do |month, entries|
  {
    "month" => month,
    "revenu" => entries.sum { |entry| entry["revenu"].to_f }
  }
end

• entries.sum adds up all the revenu values for the month. Using to_f ensures we handle any potential string values (a safe guard even though your input uses numeric values).
• The result is an array of hashes with unique months and their aggregated revenue.

Step 4: Convert Back to JSON (Optional) #

If you need the final result as a JSON string, use Rails' JSON.generate method:

merged_json = JSON.generate(merged_data)

Example Output #

After running the above code, your merged data will look like this (formatted for readability):

[
  {"month":"January","revenu":0.0},
  {"month":"February","revenu":0.0},
  {"month":"March","revenu":0.0},
  {"month":"April","revenu":0.0},
  {"month":"May","revenu":6389.216324018002},
  {"month":"June","revenu":0.0},
  {"month":"July","revenu":0.0},
  {"month":"August","revenu":0.0},
  {"month":"September","revenu":0.0},
  {"month":"October","revenu":0.0},
  {"month":"November","revenu":0.0},
  {"month":"December","revenu":0.0}
]

Bonus: Optimizing for Database Data #

If this data comes from a Rails model (e.g., a Transaction model with revenue and month attributes), you can perform grouping and summing directly in the database for better performance:

Transaction.group(:month).sum(:revenue)

This returns a hash like {"January"=>0, "May"=>6389.2163...}, which you can easily convert to your desired array format if needed.

内容的提问来源于stack exchange，提问作者shivam jindal