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A
ACS LLC
Inspiring
May 4, 2020
Answered

Working with a numeric list

  • May 4, 2020
  • 3 replies
  • 3270 views

I have a fixed numeric list, let's say that's a list of numbers from 1 to 50

 

myfixedlist=1,2,3,4,5 etc.etc

 

I then have another list which contains some of the values in the list above

 

variablelist = 10,12,20,50

 

I need to create another list that gives me all of the values in myfixedlist that is not in variablelist

 

Does anybody know of an efficient way to create this list in one swoop, using a CF command that doesn't involve a loop and lots of CFIF's

    This topic has been closed for replies.
    Correct answer ACS LLC

    Thanks @BKBK and @WolfShade. Both options work 🙂 I'm not sure which one is the most efficient, I'll have to flip a coin.

     

    I did actually just come up with something most likely a little less efficient, I created a query in memory, added the data from myfixedlist and then did a query using NOT IN, it also worked, but I suspect your options are better. I put it in here anyway as option 3.

     

    OPTION 1

    <cfscript>
    myfixedlist="7,8,9";
    variablelist = "1,2,3,4,5,6,7,10";

    listDiff = listFilter(myfixedlist,function(item){
    return listFind(variablelist,item,",") == 0;
    });
    </cfscript>

    <cfoutput>#listDiff#</cfoutput>

     

    OPTION 2
    <cfset myFixedList = "7,8,9" />

    <cfset myVarList = "1,2,3,4,5,6,7,10" />

    <cfset myNOTlist = "" />

    <cfscript>

    function getNotInFixed(item){

    if(NOT ListFind(myVarList,item)){myNOTlist = ListAppend(myNOTlist,item);}
    }

    myMap = ListMap(myFixedList,getNotInFixed);

    WriteOutput(myNOTlist);

    </cfscript>

     

    OPTION 3
    (VariableList would be set elsewhere in the code)
    <cfset MyFixedList = QueryNew("MyFixedListUID")>
    <cfset QueryAddRow(MyFixedList,3)>
    <cfset Temp = QuerySetCell(MyFixedList, "MyFixedListUID","7","1")>
    <cfset Temp = QuerySetCell(MyFixedList, "MyFixedListUID","8","2")>
    <cfset Temp = QuerySetCell(MyFixedList, "MyFixedListUID","9","3")>


    <CFQUERY DBTYPE="query" NAME="GetNewList">
    SELECT MyFixedListUID
    FROM MyFixedList
    WHERE MyFixedListUID NOT IN (<cfqueryparam value="#VariableList#" list="yes">)
    </CFQUERY>

    3 replies

    BKBK
    Community Expert
    BKBKCommunity Expert
    Community Expert
    May 5, 2020

    Use the function listFilter.

    Example:

    <cfscript>
myfixedlist="1,2,3,4,5,6,7,8,9,10";
variablelist = "2,4,6,10";

listDiff = listFilter(myfixedlist,function(item){
             return listFind(variablelist,item,",") == 0;
           });
</cfscript>

<cfoutput>#listDiff#</cfoutput>

     

    A
    ACS LLCAuthorCorrect answer
    Inspiring
    May 5, 2020

    Thanks @BKBK and @WolfShade. Both options work 🙂 I'm not sure which one is the most efficient, I'll have to flip a coin.

     

    I did actually just come up with something most likely a little less efficient, I created a query in memory, added the data from myfixedlist and then did a query using NOT IN, it also worked, but I suspect your options are better. I put it in here anyway as option 3.

     

    OPTION 1

    <cfscript>
    myfixedlist="7,8,9";
    variablelist = "1,2,3,4,5,6,7,10";

    listDiff = listFilter(myfixedlist,function(item){
    return listFind(variablelist,item,",") == 0;
    });
    </cfscript>

    <cfoutput>#listDiff#</cfoutput>

     

    OPTION 2
    <cfset myFixedList = "7,8,9" />

    <cfset myVarList = "1,2,3,4,5,6,7,10" />

    <cfset myNOTlist = "" />

    <cfscript>

    function getNotInFixed(item){

    if(NOT ListFind(myVarList,item)){myNOTlist = ListAppend(myNOTlist,item);}
    }

    myMap = ListMap(myFixedList,getNotInFixed);

    WriteOutput(myNOTlist);

    </cfscript>

     

    OPTION 3
    (VariableList would be set elsewhere in the code)
    <cfset MyFixedList = QueryNew("MyFixedListUID")>
    <cfset QueryAddRow(MyFixedList,3)>
    <cfset Temp = QuerySetCell(MyFixedList, "MyFixedListUID","7","1")>
    <cfset Temp = QuerySetCell(MyFixedList, "MyFixedListUID","8","2")>
    <cfset Temp = QuerySetCell(MyFixedList, "MyFixedListUID","9","3")>


    <CFQUERY DBTYPE="query" NAME="GetNewList">
    SELECT MyFixedListUID
    FROM MyFixedList
    WHERE MyFixedListUID NOT IN (<cfqueryparam value="#VariableList#" list="yes">)
    </CFQUERY>

    BKBK
    Community Expert
    BKBKCommunity Expert
    Community Expert
    May 5, 2020

    I don't understand. You asked initially if anybody knows "of an efficient way to create this list in one swoop, using a CF command that doesn't involve a loop and lots of CFIF's".

     

    Then you yourself come up with a solution involving a query and 5 function invocations, with one function per list element, hence an O(n) solution. That is, a solution that will grow proportionately with the length of the list. Then you proceed to mark it as part of the answer!

     

    The mind boggles. 

    WolfShade
    WolfShade
    Legend
    May 4, 2020

    D'OH!  I flaked.. add the word "function" in front of getNotInFixed().

     

    function getNotInFixed(){

     

    FACEPALM

     

    HTH,

     

    ^ _ ^

    A
    ACS LLCAuthor
    Inspiring
    May 5, 2020

    Still throwing an error 😞 It looks like there are 6 open brackets and 5 closing brackets

     

    <cfset myFixedList = "1,2,3,4" />

    <cfset myVarList = "1,2,10,12,20,45" />

    <cfset myNOTlist = "" />

    <cfscript>

    function getNotInFixed(item){

    if(NOT ListFind(myVarList,item){myNOTlist = ListAppend(myNOTlist,item);}

    }

    myMap = ListMap(myFixedList,getNotInFixed);

    WriteOutput(myNOTlist);

    </cfscript>

     

    Invalid CFML construct found on line 11 at column 40.
    ColdFusion was looking at the following text:
    {

    The CFML compiler was processing:

    A script statement beginning with if on line 11, column 9.
    A script statement beginning with function on line 9, column 4.
    A cfscript tag beginning on line 7, column 2.

    The error occurred in D:/temp/create

    WolfShade
    WolfShade
    Legend
    May 5, 2020

    I'm missing a parenthesis.

     

    if(NOT ListFind(myVarList,item)){myNOTlist = ListAppend(myNOTlist,item);}

     

    V/r,

     

    ^ _ ^

    WolfShade
    WolfShade
    Legend
    May 4, 2020

    Hello, ACS,

     

    You can use ListMap or ListReduce, this will iterate without you writing the loop code, and use a callback function to compare the value of the current index in said loop to the other list.  ONE cfif to check if that value exists in the other list.  If it does, don't add it to a new variable.

     

    <cfset myFixedList = "1,2,3,4.." />

    <cfset myVarList = "10,12,20,45.." />

    <cfset myNOTlist = "" />

    <cfscript>

        getNotInFixed(item){

            if(NOT ListFind(myVarList,item){myNOTlist = ListAppend(myNOTlist,item);}

        }

    myMap = ListMap(myFixedList,getNotInFixed);

    WriteOutput(myNOTlist);

    </cfscript>

     

    HTH,

     

    ^ _ ^

    A
    ACS LLCAuthor
    Inspiring
    May 4, 2020

    Thanks Wolfshade,

     

    I updated the values to try and obtain a result, but it threw an error

    <cfset myFixedList = "1,2,3,4" />

    <cfset myVarList = "1,2,10,12,20,45" />

    <cfset myNOTlist = "" />

    <cfscript>

    getNotInFixed(item){

    if(NOT ListFind(myVarList,item){myNOTlist = ListAppend(myNOTlist,item);}

    }

    myMap = ListMap(myFixedList,getNotInFixed);

    WriteOutput(myNOTlist);

    </cfscript>

     

    ERROR:

    Invalid construct.
    A script statement must end with ";".

    The CFML compiler was processing:

    A script statement beginning with getNotInFixed on line 9, column 5.
    A cfscript tag beginning on line 7, column 2.


    The error occurred in D:/temp/createfreetoplaylist.cfm: line 9

    7 : <cfscript>
    8 :
    9 : getNotInFixed(item){
    10 :
    11 : if(NOT ListFind(myVarList,item){myNOTlist = ListAppend(myNOTlist,item);}

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