Various ways to solve JavaScript array problems_javascript skills

a1=['020','021',..........'025',..........];
a2=[' Shanghai','Tianjin',.........'Nanjing',..........];
length is the same length and corresponds one to one. How to get 025 in a1 Corresponding to Nanjing of a2?

I thought of a way, but it used a lot of evals and loops, which didn’t feel very good:

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As long as you are sure The numbering position is three digits,
and then it’s ok!

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This is the implementation method of array

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Advice from experts If I were completing a similar function, I wouldn't choose an array;

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<script> var a1=['020','021','025'],a2=['上海','天津','南京']; var obj=function(){ for(var i=0;i<a1.length;i++){ eval("this.a"+a1[i]+"='"+a2[i]+"';") } this.getA=function(m){ return (eval("this.a"+m)) } } var obj2=new obj; alert(obj2.getA('025')) </script><script> var a1=['020','021','025','999'],a2=['上海','天津','南京','xpxp']; alert(a2[(a1.join().indexOf('021'))/4]); </script><script> var a1=['020','021','025'],a2=['上海','天津','南京']; function getCity(n){ for(var i=0, l=a1.length; i<l; i++) if(n==a1[i])return a2[i]; } alert(getCity("025")) </script>