我需要做一个简单的字符串分割,但似乎没有一个函数,我测试的手动方式似乎不起作用。我该怎么做呢?


当前回答

我喜欢这个简短的解决方案

function split(s, delimiter)
    result = {};
    for match in (s..delimiter):gmatch("(.-)"..delimiter) do
        table.insert(result, match);
    end
    return result;
end

其他回答

我喜欢这个简短的解决方案

function split(s, delimiter)
    result = {};
    for match in (s..delimiter):gmatch("(.-)"..delimiter) do
        table.insert(result, match);
    end
    return result;
end

根据用例,这可能是有用的。它将剪切标志两侧的所有文本:

b = "This is a string used for testing"

--Removes unwanted text
c = (b:match("a([^/]+)used"))

print (c)

输出:

string

你可以使用这个方法:

function string:split(delimiter)
  local result = { }
  local from  = 1
  local delim_from, delim_to = string.find( self, delimiter, from  )
  while delim_from do
    table.insert( result, string.sub( self, from , delim_from-1 ) )
    from  = delim_to + 1
    delim_from, delim_to = string.find( self, delimiter, from  )
  end
  table.insert( result, string.sub( self, from  ) )
  return result
end

delimiter = string.split(stringtodelimite,pattern) 

对于那些从“在Lua中编程”这本书的练习10.1中学习过的人来说,似乎很清楚我们不能使用后面书中解释的概念(迭代器),而且函数应该接受多个字符分隔符。

split()是一个让模式匹配不需要的内容(split)并在空字符串上返回一个空表的技巧。plainSplit()的返回更像其他语言中的split。

magic = "([%%%.%(%)%+%*%?%[%]%^%$])"

function split(str, sep, plain)
    if plain then sep = string.gsub(sep, magic, "%%%1") end
    
    local N = '\255'
    str = N..str..N
    str = string.gsub(str, sep, N..N)

    local result = {}
    for word in string.gmatch(str, N.."(.-)"..N) do
        if word ~= "" then
            table.insert(result, word)
        end
    end
    return result
end


function plainSplit(str, sep)
    sep = string.gsub(sep, magic, "%%%1")

    local result = {}
    local start = 0
    repeat
        start = start + 1

        local from, to = string.find(str, sep, start)
        from = from and from-1
        
        local word = string.sub(str, start, from, true)
        table.insert(result, word)

        start = to
    until start == nil

    return result
end


function tableToString(t)
    local ret = "{"
    for _, word in ipairs(t) do
        ret = ret .. '"' .. word .. '", '
    end
    ret = string.sub(ret, 1, -3)
    ret = ret .. "}"

    return #ret > 1 and ret or "{}"
end

function runSplit(func, title, str, sep, plain)
    print("\n" .. title)
    print("str: '"..str.."'")
    print("sep: '"..sep.."'")
    local t = func(str, sep, plain)
    print("-- t = " .. tableToString(t))
end



print("\n\n\n=== Pattern split ===")
runSplit(split, "Exercice 10.1", "a whole new world", " ")
runSplit(split, "With trailing seperator", "  a  whole   new world  ", " ")
runSplit(split, "A word seperator", "a whole new world", " whole ")
runSplit(split, "Pattern seperator", "a1whole2new3world", "%d")
runSplit(split, "Magic characters as plain seperator", "a$.%whole$.%new$.%world", "$.%", true)
runSplit(split, "Control seperator", "a\0whole\1new\2world", "%c")
runSplit(split, "ISO Time", "2020-07-10T15:00:00.000", "[T:%-%.]")

runSplit(split, " === [Fails] with \\255 ===", "a\255whole\0new\0world", "\0", true)

runSplit(split, "How does your function handle empty string?", "", " ")



print("\n\n\n=== Plain split ===")
runSplit(plainSplit, "Exercice 10.1", "a whole new world", " ")
runSplit(plainSplit, "With trailing seperator", "  a  whole   new world  ", " ")
runSplit(plainSplit, "A word seperator", "a whole new world", " whole ")
runSplit(plainSplit, "Magic characters as plain seperator", "a$.%whole$.%new$.%world", "$.%")

runSplit(plainSplit, "How does your function handle empty string?", "", " ")

输出

=== Pattern split ===

Exercice 10.1
str: 'a whole new world'
sep: ' '
-- t = {"a", "whole", "new", "world"}

With trailing seperator
str: '  a  whole   new world  '
sep: ' '
-- t = {"a", "whole", "new", "world"}

A word seperator
str: 'a whole new world'
sep: ' whole '
-- t = {"a", "new world"}

Pattern seperator
str: 'a1whole2new3world'
sep: '%d'
-- t = {"a", "whole", "new", "world"}

Magic characters as plain seperator
str: 'a$.%whole$.%new$.%world'
sep: '$.%'
-- t = {"a", "whole", "new", "world"}

Control seperator
str: 'awholenewworld'
sep: '%c'
-- t = {"a", "whole", "new", "world"}

ISO Time
str: '2020-07-10T15:00:00.000'
sep: '[T:%-%.]'
-- t = {"2020", "07", "10", "15", "00", "00", "000"}

 === [Fails] with \255 ===
str: 'a�wholenewworld'
sep: ''
-- t = {"a"}

How does your function handle empty string?
str: ''
sep: ' '
-- t = {}



=== Plain split ===

Exercice 10.1
str: 'a whole new world'
sep: ' '
-- t = {"a", "whole", "new", "world"}

With trailing seperator
str: '  a  whole   new world  '
sep: ' '
-- t = {"", "", "a", "", "whole", "", "", "new", "world", "", ""}

A word seperator
str: 'a whole new world'
sep: ' whole '
-- t = {"a", "new world"}

Magic characters as plain seperator
str: 'a$.%whole$.%new$.%world'
sep: '$.%'
-- t = {"a", "whole", "new", "world"}

How does your function handle empty string?
str: ''
sep: ' '
-- t = {""}

就像字符串一样。Gmatch将查找字符串中的模式,这个函数将查找模式之间的内容:

function string:split(pat)
  pat = pat or '%s+'
  local st, g = 1, self:gmatch("()("..pat..")")
  local function getter(segs, seps, sep, cap1, ...)
    st = sep and seps + #sep
    return self:sub(segs, (seps or 0) - 1), cap1 or sep, ...
  end
  return function() if st then return getter(st, g()) end end
end

默认情况下,它返回由空格分隔的任何内容。