Using braces with dynamic variable names in PHP

Question

I m trying to use dynamic variable names  I m not sure what they re actually called  But pretty much like this   for  i 0   i lt  2   i             file     i    file  filelist  i       var dump  file0     The return is null which tells me it s not working  I have no idea what the syntax or the technique I m looking for is here  which makes it hard to research   filelist is defined earlier on

User · Answer

I was in a position where I had 6 identical arrays and I needed to pick the right one depending on another variable and then assign values to it. In the case shown here $comp_cat was 'a' so I needed to pick my 'a' array ( I also of course had 'b' to 'f' arrays)

Note that the values for the position of the variable in the array go after the closing brace.

${'comp_cat_'.$comp_cat.'_arr'}[1][0] = "FRED BLOGGS";

${'comp_cat_'.$comp_cat.'_arr'}[1][1] = $file_tidy;

echo 'First array value is '.$comp_cat_a_arr[1][0].' and the second value is .$comp_cat_a_arr[1][1];

User · Answer

I do this quite often on results returned from a query    e g       MyQueryResult is an array of results from a query  foreach   MyQueryResult as  key  gt  value          key   value      Now I can just use  MyFieldname  which is easier in echo statements etc  rather than  MyQueryResult  MyFieldname    Yep  it s probably lazy  but I ve never had any problems

User · Answer

i have a solution for dynamically created variable value and combined all value in a variable   if   SERVER  REQUEST METHOD     POST         r 0      for  i 1   i lt  4   i              a     POST  a   i            r     a            echo  r

User · Answer

Wrap them in         file     i    file  filelist  i      Working Example    Using     is a way to create dynamic variables  simple example      a     b      hello there   echo  ab     hello there

User · Answer

Try using    instead of         file   i    file  filelist  i

User · Answer

Try using    instead of         file   i    file  filelist  i

User · Answer

Tom if you have existing array you can convert that array to object and use it like this    r    object   MyQueryResult  echo  r- gt key

User · Answer

Overview In PHP  you can just put an extra   in front of a variable to make it a dynamic variable     variableName    value   While I wouldn t recommend it  you could even chain this behavior           DoNotTryThisAtHomeKids    value   You can but are not forced to put  variableName between         variableName     value   Using    is only mandatory when the name of your variable is itself a composition of multiple values  like this      variableNamePart1    variableNamePart2     value   It is nevertheless recommended to always use     because it s more readable  Differences between PHP5 and PHP7 Another reason to always use     is that PHP5 and PHP7 have a slightly different way of dealing with dynamic variables  which results in a different outcome in some cases  In PHP7  dynamic variables  properties  and methods will now be evaluated strictly in left-to-right order  as opposed to the mix of special cases in PHP5  The examples below show how the order of evaluation has changed  Case 1     foo  bar    baz    PHP5 interpetation      foo  bar    baz    PHP7 interpetation      foo   bar    baz    Case 2    foo- gt  bar  baz    PHP5 interpetation    foo- gt   bar  baz    PHP7 interpetation    foo- gt   bar   baz    Case 3    foo- gt  bar  baz      PHP5 interpetation    foo- gt   bar  baz      PHP7 interpetation    foo- gt   bar   baz      Case 4   Foo   bar  baz      PHP5 interpetation   Foo    bar  baz      PHP7 interpetation   Foo    bar   baz

[php] Using braces with dynamic variable names in PHP

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