在 Ruby 中读取 CSV 时如何跳过标题行？
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How can I skip the header row when reading a CSV in Ruby?
提问by slhck
Ruby's CSVclass makes it pretty easy to iterate over each row:
Ruby 的CSV类使迭代每一行变得非常容易：
CSV.foreach(file) { |row| puts row }
However, this always includes the header row, so I'll get as output:
但是，这始终包括标题行，因此我将获得输出：
header1, header2
foo, bar
baz, yak
I don't want the headers though. Now, when I call …
不过我不想要标题。现在，当我打电话...
CSV.foreach(file, :headers => true)
I get this result:
我得到这个结果：
#<CSV::Row:0x10112e510
@header_row = false,
attr_reader :row = [
[0] [
[0] "header1",
[1] "foo"
],
[1] [
[0] "header2",
[1] "bar"
]
]
>
Of course, because the documentation says:
当然，因为文档说：
This setting causes #shift to return rows as CSV::Row objects instead of Arrays
此设置导致 #shift 将行作为 CSV::Row 对象而不是数组返回
But, how can I skip the header row, returning the row as a simple array?I don't want the complicated CSV::Rowobject to be returned.
但是，如何跳过标题行，将该行作为简单数组返回？我不希望CSV::Row返回复杂的对象。
I definitely don't want to do this:
我绝对不想这样做：
first = true
CSV.foreach(file) do |row|
if first
puts row
first = false
else
# code for other rows
end
end
回答by waldyr.ar
Look at #shiftfrom CSV Class:
从 CSV 类中查看#shift：
The primary read method for wrapped Strings and IOs, a single row is pulled from the data source, parsed and returned as an Array of fields (if header rows are not used)
包装字符串和 IO 的主要读取方法，从数据源中提取单行，解析并作为字段数组返回（如果不使用标题行）
An Example:
一个例子：
require 'csv'
# CSV FILE
# name, surname, location
# Mark, Needham, Sydney
# David, Smith, London
def parse_csv_file_for_names(path_to_csv)
names = []
csv_contents = CSV.read(path_to_csv)
csv_contents.shift
csv_contents.each do |row|
names << row[0]
end
return names
end
回答by jodell
回答by agarie
A cool way to ignore the headers is to read it as an array and ignore the first row:
忽略标题的一种很酷的方法是将其作为数组读取并忽略第一行：
data = CSV.read("dataset.csv")[1 .. -1]
# => [["first_row", "with data"],
["second_row", "and more data"],
...
["last_row", "finally"]]
The problem with the :headers => falseapproach is that CSVwon't try to read the first row as a header, but will consider it part of the data. So, basically, you have a useless first row.
该:headers => false方法的问题在于CSV不会尝试将第一行作为标题读取，而是将其视为数据的一部分。所以，基本上，你有一个无用的第一行。
