php - Incrementing an array's value is causing warnings in the log -


i trying create array holds count of each course offer based on location , instructor. here sample code

$coursecnt = array(); foreach($courselist $course){       $coursecnt[$course['location']][$course['instructor']] += 1 }

this code creates array , displays bunch of warnings like:

unidentified index "orlando" locations, unidentified index "john smith" instructor

i have found if make = 1 instead of += 1 warnings go away of course makes every course location/instructor 1 not good.

my next though checking if exists, if doesn't, make 1 , if += 1. here example

if(isset($coursecnt[$course['location']][$course['instructor']]){      $coursecnt[$course['location']][$course['instructor']] += 1 }else{      $coursecnt[$course['location']][$course['instructor']] = 1 }

this results in fatal error:

cannot use string offset array

$course array structure 2 dimensional array pulled sql

sample:

courseid   location   instructor 1          orlando    john smith 2          detroit    bill murray

you not checking if location exists before checking instructor in first line of new version of code. need check if exists , create in $coursecnt array if doesn't (as empty array). after that, can check instructor:

// initialise empty array $coursecnt = array();  // create location if not in array if( ! isset($coursecnt[$course['location']])) {    $coursecnt[$course['location']] = array(); }  // either increment instructor or create initial value of 1 if ( isset($coursecnt[$course['location']][$coursecnt[$course['instructor']]]) ) {   $coursecnt[$course['location']][$coursecnt[$course['instructor']]] += 1; } else {   $coursecnt[$course['location']][$coursecnt[$course['instructor']]] = 1; }

you've got lot of square brackets going on in there, might find easier read if use php's array_key_exists (documentation) instead of isset:

// initialise empty array $coursecnt = array();  // create location if not in array if( ! array_key_exists($course['location'], $coursecnt)) {    $coursecnt[$course['location']] = array(); }  // either increment instructor or create initial value of 1 if ( array_key_exists($course['instructor'], $coursecnt[$course['location']]) ) {   $coursecnt[$course['location']][$coursecnt[$course['instructor']]] += 1; } else {   $coursecnt[$course['location']][$coursecnt[$course['instructor']]] = 1; }

Comments

Post a Comment

Popular posts from this blog

c++ - Difference between pre and post decrement in recursive function argument -

i have following sample code used pre-decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(--c); cout << c << endl; return; } } this function give output input 4 : dp3 dp2 dp1 dp0 0 1 2 3 but when use post decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(c--); cout << c << endl; return; } } output goes in infinite loop dp4 can explain me in detail why happens ? this happens because function(c--) called same value of c , when finishes c decremented. recursively called, hence called same value no chance of return , hit stack overflow error. assume this, int x = 1, y = 0; y = x++ result y == 1 , x == 2. if y = ++x , bot x , y 2.
Read more

php - Nothing but 'run(); ' when browsing to my local project, how do I fix this? -

i added new project. made mistake in projectname.conf file in sites-available apache2, led me reinstalling apache2. after reinstalling , re-enabling projects on every page of every project .. <body> run(); </body> .. i've run composer update, restarted service, restarted pc, checked config files, tried disabling new project. there nothing in error log, , access.log: 127.0.0.1 - - [15/may/2015:01:40:47 +0200] "get / http/1.1" 304 181 "-" "mozilla/5.0 (x11; ubuntu; linux x86_64; rv:38.0) gecko/20100101 firefox/38.0" maybe i'm forgetting apache2 reinstall? don't think did different last time installed it. looks haven't setup php correctly. take @ this great guide , maybe you're forgetting link php config apache2.
Read more

php - How can I echo out this array? -

i don't know how go grabbing data in variable , put foreach loop. class tree{ private $info = array( array('name'=>'jim','state'=>'nu','company'=>'nu','phone'=>array('cell'=>'5615111111','office'=>'5611111111'),'email'=>array('primary'=>'exs@example.com','ex@there.com')), array('name'=>'joe smith','city'=>'phoenix','phone'=>'4805551111','email'=>'jsmith@some_email.com'), array('name'=>'john doe','city'=>'chandler','company'=>'doe co.','email'=>array('jdoe@gmail.com','personal'=>'email@email.com'),'phone'=>'6025550002') ); } if you're inside of class, can access private variable using $this->variablename . example, i...
Read more