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
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)
其他回答
很多答案只接受单字符分隔符,或者不能很好地处理边缘情况(例如空分隔符),所以我认为我将提供一个更明确的解决方案。
这里有两个函数,gsplit和split,改编自Scribunto MediaWiki扩展中的代码,用于维基百科等维基。该代码在GPL v2下获得许可。我已经更改了变量名,并添加了注释,使代码更容易理解,我还更改了代码,使用常规的Lua字符串模式,而不是Scribunto的Unicode字符串模式。原始代码在这里有测试用例。
-- gsplit: iterate over substrings in a string separated by a pattern
--
-- Parameters:
-- text (string) - the string to iterate over
-- pattern (string) - the separator pattern
-- plain (boolean) - if true (or truthy), pattern is interpreted as a plain
-- string, not a Lua pattern
--
-- Returns: iterator
--
-- Usage:
-- for substr in gsplit(text, pattern, plain) do
-- doSomething(substr)
-- end
local function gsplit(text, pattern, plain)
local splitStart, length = 1, #text
return function ()
if splitStart then
local sepStart, sepEnd = string.find(text, pattern, splitStart, plain)
local ret
if not sepStart then
ret = string.sub(text, splitStart)
splitStart = nil
elseif sepEnd < sepStart then
-- Empty separator!
ret = string.sub(text, splitStart, sepStart)
if sepStart < length then
splitStart = sepStart + 1
else
splitStart = nil
end
else
ret = sepStart > splitStart and string.sub(text, splitStart, sepStart - 1) or ''
splitStart = sepEnd + 1
end
return ret
end
end
end
-- split: split a string into substrings separated by a pattern.
--
-- Parameters:
-- text (string) - the string to iterate over
-- pattern (string) - the separator pattern
-- plain (boolean) - if true (or truthy), pattern is interpreted as a plain
-- string, not a Lua pattern
--
-- Returns: table (a sequence table containing the substrings)
local function split(text, pattern, plain)
local ret = {}
for match in gsplit(text, pattern, plain) do
table.insert(ret, match)
end
return ret
end
split函数的一些例子:
local function printSequence(t)
print(unpack(t))
end
printSequence(split('foo, bar,baz', ',%s*')) -- foo bar baz
printSequence(split('foo, bar,baz', ',%s*', true)) -- foo, bar,baz
printSequence(split('foo', '')) -- f o o
你可以使用penlight图书馆。它有一个使用分隔符分割字符串的函数,输出列表。
它实现了许多我们在编程时可能需要和Lua中缺少的功能。
下面是使用它的示例。
>
> stringx = require "pl.stringx"
>
> str = "welcome to the world of lua"
>
> arr = stringx.split(str, " ")
>
> arr
{welcome,to,the,world,of,lua}
>
我发现许多其他答案都有失败的边缘情况(例如。当给定的字符串包含#,{或}字符,或给定的分隔符,如%,需要转义)。下面是我使用的实现:
local function newsplit(delimiter, str)
assert(type(delimiter) == "string")
assert(#delimiter > 0, "Must provide non empty delimiter")
-- Add escape characters if delimiter requires it
delimiter = delimiter:gsub("[%(%)%.%%%+%-%*%?%[%]%^%$]", "%%%0")
local start_index = 1
local result = {}
while true do
local delimiter_index, _ = str:find(delimiter, start_index)
if delimiter_index == nil then
table.insert(result, str:sub(start_index))
break
end
table.insert(result, str:sub(start_index, delimiter_index - 1))
start_index = delimiter_index + 1
end
return result
end
下面是一个在Lua 4.0中工作的例程,返回inputstr中由sep分隔的子字符串的表t:
function string_split(inputstr, sep)
local inputstr = inputstr .. sep
local idx, inc, t = 0, 1, {}
local idx_prev, substr
repeat
idx_prev = idx
inputstr = strsub(inputstr, idx + 1, -1) -- chop off the beginning of the string containing the match last found by strfind (or initially, nothing); keep the rest (or initially, all)
idx = strfind(inputstr, sep) -- find the 0-based r_index of the first occurrence of separator
if idx == nil then break end -- quit if nothing's found
substr = strsub(inputstr, 0, idx) -- extract the substring occurring before the separator (i.e., data field before the next delimiter)
substr = gsub(substr, "[%c" .. sep .. " ]", "") -- eliminate control characters, separator and spaces
t[inc] = substr -- store the substring (i.e., data field)
inc = inc + 1 -- iterate to next
until idx == nil
return t
end
这个简单的测试
inputstr = "the brown lazy fox jumped over the fat grey hen ... or something."
sep = " "
t = {}
t = string_split(inputstr,sep)
for i=1,15 do
print(i, t[i])
end
收益率:
--> t[1]=the
--> t[2]=brown
--> t[3]=lazy
--> t[4]=fox
--> t[5]=jumped
--> t[6]=over
--> t[7]=the
--> t[8]=fat
--> t[9]=grey
--> t[10]=hen
--> t[11]=...
--> t[12]=or
--> t[13]=something.
只是坐在分隔符上
local str = 'one,two'
local regxEverythingExceptComma = '([^,]+)'
for x in string.gmatch(str, regxEverythingExceptComma) do
print(x)
end
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