PHP Weird output by simple code

Question

I have this code with me and it is giving "aababc" in output i am not sure why this behaving like this.

<?php
    $str = ‘abcdefghijklmnop’;
    $fp = fopen(“output.txt”, ‘w’);
    for($i=0; $i< 4; $i++) {
    fwrite($fp, $str, $i);
    }
    ?>

Any Guru having any idea on this.

Thanks

Well, the 3rd parameter of fwrite is a length limit, so basically your code writes to output.txt: the first letter (i = 0, a) then the first 2 letters (i = 1, ab) and finally, when i = 3 it writes: abc with results: aababc. if you wanted to write the first 3 letters of your $str you should: fwrite($fp, $str[$i]); good luck. — Guy S
– Guy S, Commented Jun 16, 2013 at 12:32

u_mulder · Accepted Answer · 2013-06-16 12:41:59Z

4

Here how your for-loop works:

// i = 0;
fwrite($fp, $str, 0); // writes nothing
// i = 1;
fwrite($fp, $str, 1); // writes a
// i = 2;
fwrite($fp, $str, 2); // writes ab
// i = 3;
fwrite($fp, $str, 3); // writes abc
// total write 'aababc'

UPDATE: And to achive your goal:

for ($i = 0; $i < 4; $i++) {
   fwrite($fp, substr($str, $i, 1));
}
// will write 'abcd'

I cant stop) Or without loop:

// will take 3 first symbols from string and write to file
fwrite($fp, substr($str, 0, 3));
// will write 3 symbols from string to file
fwrite($fp, $str, 3);

edited Jun 16, 2013 at 12:41

answered Jun 16, 2013 at 12:34

u_mulder

54.8k5 gold badges54 silver badges72 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

u_mulder Over a year ago

use substr to get the proper symbol you need

gmaliar · Accepted Answer · 2013-06-16 12:34:56Z

1

It behaves correctly.

i = 0 str = ''

i = 1 str = 'a'

i = 2 str = 'ab'

i = 3 str = 'abc'

so it writes to the end of it every time what's in $str until length $i.

answered Jun 16, 2013 at 12:34

gmaliar

5,4791 gold badge30 silver badges36 bronze badges

Comments

Perry · Accepted Answer · 2013-06-16 12:37:35Z

0

You need to change the fwrite from this

fwrite($fp, $str, $i);

to this:

fwrite($fp, substr($str, $i, 1));

To get the expected result 'abc'

answered Jun 16, 2013 at 12:37

Perry

11.7k2 gold badges30 silver badges38 bronze badges

1 Comment

u_mulder Over a year ago

Nope( substr($str, $i, 1) is better)

Collectives™ on Stack Overflow

PHP Weird output by simple code

3 Answers 3

1 Comment

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related