julia - 扫描文本文件每行最多 N 个单词，用 Julia 中的单词列和行填充数组。事先不知道字数

Question

我只有部分解决方案

data = split.(readlines(file))
a =  map(x -> x[1],data)
b =  map(x -> x[2],data)
c =  map(x -> x[3],data)
d =  map(x -> x[4],data)
e =  map(x -> x[5],data)
f =  map(x -> x[6],data)

但仅当所有输入行都包含完整的预期单词数时，它才有效。不幸的是，行可以更短，我想用空字符串“”或一些原生的 Julia 优点来填充缺失值的“空词”。

可以看出，我是 Julia 新手。

谢谢

Answer 1

这是一个如何做到这一点的示例(我添加了注释和解释):

julia> str = """
       a b c
       a b
       a b c d
       a
       a b c d e
       """ # source data
"a b c\na b\na b c d\na\na b c d e\n"

julia> data = split.(readlines(IOBuffer(str))) # use IOBuffer to turn string into file-like object
5-element Vector{Vector{SubString{String}}}:
 ["a", "b", "c"]
 ["a", "b"]
 ["a", "b", "c", "d"]
 ["a"]
 ["a", "b", "c", "d", "e"]

julia> res = fill("", length(data), maximum(length, data)) # pre-fill matrix with "" as you requested - this should probably be easiest for you to work with
5×5 Matrix{String}:
 ""  ""  ""  ""  ""
 ""  ""  ""  ""  ""
 ""  ""  ""  ""  ""
 ""  ""  ""  ""  ""
 ""  ""  ""  ""  ""

julia> foreach(((out, in),) -> copyto!(out, in), zip(eachrow(res), data)) # fill each row of res with consecutive elements of data using copyto!

julia> res # the result you wanted is now in res
5×5 Matrix{String}:
 "a"  "b"  "c"  ""   ""
 "a"  "b"  ""   ""   ""
 "a"  "b"  "c"  "d"  ""
 "a"  ""   ""   ""   ""
 "a"  "b"  "c"  "d"  "e"

如有不清楚的地方请评论。因此，您将得到一个矩阵，其每一行都是源数据的行。

按键操作的更高级模式是:

foreach(Base.splat(copyto!), zip(eachrow(res), data))

如果您都不清楚，您也可以选择双循环，例如:

for i in 1:length(data)
    row = data[i]
    for j in 1:length(row)
        res[i, j] = row[j]
    end
end