Write single element of array to fwrite file - php

Question

I'm trying to return an array from MyArray function and use [0] to write2file and use [1] to populate pushover(myArray($jason)). I have tried fwrite($myfile, echo $txt[0]); but this fails and only writes the word 'Array' to the file instead of contents of array. I've looked at print_r and implode but no luck.
write2file(myArray($json));
compare2files('old_version.txt', 'new_version.txt');
if (compare2files('old_version.txt', 'new_version.txt') == 'false') {
pushover(implode("\n",myArray($json)[1]));
rename("new_version.txt", "old_version.txt");
}
function write2file($txt) {
$myfile = fopen("new_version.txt", "w") or die("Unable to open file!");
fwrite($myfile, implode("\n",$txt[0]));
fclose($myfile);
}
function compare2files($file1, $file2) {
$file3 = file_get_contents($file1);
$file4 = file_get_contents($file2);
if (strcmp($file3, $file4) !== 0) {
return 'false';
}
}
function myArray($arry) {
$selected = array(5,6,7,10,12,15,17,18,22,24);
foreach($arry as $key => $value) {
if (in_array($key, $selected) || empty($selected)) {
$result .= $value['name']. chr(10);
$xTime .= $value['name']. chr(10);
$length = count($value["color"]);
for ($i = 0; $i < $length; $i++) {
if($value['time'][$i] != "") {
if(preg_match('/#ff0000/', $value['color'][$i])) {
$value['color'][$i] = 'RED';
}
if(preg_match('/#ffff00/', $value['color'][$i])) {
$value['color'][$i] = 'YELLOW';
}
if(preg_match('/#006600/', $value['color'][$i])) {
$value['color'][$i] = 'GREEN (Mini Disaster)';
}
if(preg_match('/#9933cc/', $value['color'][$i])) {
$value['color'][$i] = 'PURPLE (Trauma ByPass)';
}
if(preg_match('/#ff6600/', $value['color'][$i])) {
$value['color'][$i] = 'ORANGE (ReRoute)';
}
$xTime .= ' ' . $value["color"][$i] . ' - ' . $value["time"][$i] . chr(10);
$xColor .= ' ' . $value["color"][$i] . chr(10);
$results[0] = $xTime;
$results[1] = $xColor;
}
}
}
}
return $results;
}