Difference between revisions of "John's hacks"

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Line 54: Line 54:
  
 
== Passing shell args (PHP) ==
 
== Passing shell args (PHP) ==
 +
 +
Put your args in $args and use escapeshellarg() to escape them...
  
 
  $args = join( ' ', array_map( 'escapeshellarg', $args ) );
 
  $args = join( ' ', array_map( 'escapeshellarg', $args ) );
 
   
 
   
 
  exec( "$program $args" );
 
  exec( "$program $args" );

Revision as of 02:55, 16 April 2020

I decided I might start documenting some hacks I've come across in my travels which I think are neat.

Removing last comma (PHP)

Sometimes you're processing a list to build a string and you want a comma after all items except the last one. You can do that like this:

// 2020-04-14 jj5 - it's important to handle this case...
//
if ( count( $list ) === 0 ) { return 'list is empty'; }

$result = 'my list: ';
$is_first = true;

foreach ( $list as $item ) {

  if ( $is_first ) {

    $is_first = false;

  }
  else {

    $result .= ', ';

  }

  $result .= $item;

}

return $result . '.';

But that can be simplified like this:

// 2020-04-14 jj5 - it's important to handle this case...
//
if ( count( $list ) === 0 ) { return 'list is empty'; }

$result = 'my list: ';

foreach ( $list as $item ) {

  $result .= "$item, ";

}

// 2020-04-14 jj5 - the neat hack is dropping the last two characters here...
//
return substr( $result, 0, -2 ) . '.';

Although the whole thing can often (but not always) be simplified as something like this (you might also need to check for an empty list):

return 'my list: ' . implode( ', ', $list ) . '.';

Passing shell args (PHP)

Put your args in $args and use escapeshellarg() to escape them...

$args = join( ' ', array_map( 'escapeshellarg', $args ) );

exec( "$program $args" );