本文介绍了在ruby中智能地将散列数组转换为CSV的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我需要转换CSV文件中的散列数组。我发现的各种方法涉及到在数组中插入散列值:
I need to convert an array of hashes in a CSV file. The various methods I found involve inserting in the array the hash values:
class Array
def to_csv(csv_filename="hash.csv")
require 'csv'
CSV.open(csv_filename, "wb") do |csv|
csv << first.keys # adds the attributes name on the first line
self.each do |hash|
csv << hash.values
end
end
end
end
不幸的是,这个方法需要数组中的每个元素都是完整的,例如当我有这个数组,甚至不会返回一个有效的csv:
Unfortunately this method requires that each element in the array is complete, for example when I have this array it won't even return a valid csv:
myarray = [
{foo: 1, bar: 2, baz: 3},
{bar: 2, baz: 3},
{foo: 2, bar: 4, baz: 9, zab: 44}
]
推荐答案
创建一个csv以找到所有可能的标头,并按正确的顺序分配值,
如何:
What about:
class Array
def to_csv(csv_filename="hash.csv")
require 'csv'
# Get all unique keys into an array:
keys = self.flat_map(&:keys).uniq
CSV.open(csv_filename, "wb") do |csv|
csv << keys
self.each do |hash|
# fetch values at keys location, inserting null if not found.
csv << hash.values_at(*keys)
end
end
end
end
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