Freemarker：使用拆分将字符串转换为列表然后迭代

Question

我需要遍历由 "split" 内置的列表，但我还没有成功。

我有两个日期列表，其中一些日期相同。使用 "seq_index_of" 作为 "Vlookup" 我能够找到相关性并获得两个列表中的日期索引。但是，"seq_index_of" 给出了一个字符串、数字、布尔值或 date/time 值输出，而不是一个序列（供我迭代）。

我用"split"把字符串变成序列。不过，split 不会真正完成这项工作。

first i use seq_index_of for the two lists:
this will give me the index of correlated dates.
<#assign result>
<#list list1 as L1> 
${list2?seq_index_of(L1)}
</#list>
</#assign>
---------------------------------------
next I iterate the result. for this, imagine "array" is the result from above:
ex 1. this does not work. cant iterate

<#assign array = "2020-10-02,2021-10-04,2022-10-04,2023-10-04" />
<#assign mappedArray_string = []>
<#list array?split(",") as item>
<#assign mappedArray_string += [item]>
</#list>

${"is_sequence: " + mappedArray_string?is_sequence?c}

<#--print the list-->
<#list mappedArray_string as m>
<#--i cant do ?string("MM/dd/yyyy") or ant other iteration
${m?string("MM/dd/yyyy")}
<#if m?has_next>${";"}<#else>${"and"}</#if>-->
<#with no iteration, this will work. not what i need-->
${m}
</#list>
+++++++++++++++++++++++++++++++++++++++++++++
ex 2. - this works with a regular numerical list
<#assign array = [100, 200, 300, 400, 500] />
<#assign mappedArray_numbers = []>
<#list array as item>
<#assign mappedArray_numbers += [item]>
</#list>

${"is_sequence: " + mappedArray_numbers?is_sequence?c}

<#--print the list-->
<#list mappedArray_numbers as m>
${m?string("##0.0")}<#-- able to iterate-->
</#list>```

expected:
date1 ; date2 ; date3 and lastdate

error:
For "...(...)" callee: Expected a method, but this has evaluated to a string (wrapper: f.t.SimpleScalar):
==> m?string  [in template "preview-template" at line 27, column 3]

----
FTL stack trace ("~" means nesting-related):
 - Failed at: ${m?string("MM/dd/yyyy")}

Answer 1

如果您想列出 list2 中也出现在 list1 中的项目，请执行此操作（由于 ?filter，需要 FreeMarker 2.3.29）：

<#list list2?filter(it -> list1?seq_contains(it)) as d>
  ${d?string('MM/dd/yyyy')}
</#list>

2.3.29 之前：

<#list list2 as d>
  <#if list1?seq_contains(d)>
    ${d?string('MM/dd/yyyy')}
  </#if>
</#list>

Freemarker：使用拆分将字符串转换为列表然后迭代

Freemarker: convert sting to list with split then iterate

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