php 判断月度中最小的日期

php 判断月份中最小的日期
比如：一个数组里边装的日期：2014-01-01,2014-01-02,2014-01-22，2014-02-22,2014-02-26,2014-03-03,2014-03-25,2014-03-28

要达到：把月份中最小的日期取出来，如下所示：

2014-01-01

2014-02-22

2014-03-03

并且计算月份所属日期数：（比如1月份有3个（2014-01-01,2014-01-02,2014-01-22））

01月份-》3

02月份-》2

03月份-》3

这两个功能单独写。请大侠赐教，谢谢！！！！！！！！！


------解决方案--------------------

$ar = array(<br />  '2014-01-01',<br />  '2014-01-02',<br />  '2014-01-22',<br />  '2014-02-22',<br />  '2014-02-26',<br />  '2014-03-03',<br />  '2014-03-25',<br />  '2014-03-28',<br />);<br />$r1 = $r2 = array();<br />foreach($ar as $d) {<br />  list($y, $m, $d) = explode('-', $d);<br />  if(! isset($r1[$y.$m])) $r1[$y.$m] = 32;<br />  $r1[$y.$m] = min($r1[$y.$m], $d);<br />  if(! isset($r2[$y.$m])) $r2[$y.$m] = 0;<br />  $r2[$y.$m]++;<br />}<br />print_r($r1);<br />print_r($r2);<br />

Array
(
    [201401] => 01
    [201402] => 22
    [201403] => 03
)
Array
(
    [201401] => 3
    [201402] => 2
    [201403] => 3
)

------解决方案--------------------
1.

$arr = array('2014-01-01','2014-01-02','2014-01-22','2014-02-22','2014-02-26','2014-03-03','2014-03-25','2014-03-28');<br />sort($arr);<br />$out = array();<br />foreach ($arr as $key => $value) {<br />	$mouth = date('n',strtotime($value));<br />	if(!in_array($mouth, array_keys($out))) $out[$mouth] = $value;<br />}<br />var_dump($out);

2.

$arr = array('2014-01-01','2014-01-02','2014-01-22','2014-02-22','2014-02-26','2014-03-03','2014-03-25','2014-03-28');<br />$newArr = array_map('cout', $arr);<br />function cout($n){<br />	return date('n',strtotime($n));<br />}<br />print_r ( array_count_values ( $newArr ));

------解决方案--------------------
如果要考虑不同年相同月份的情况，例如2014-02 与 2013-02 需要分开统计。key的值要用Y-m格式。

<br /><?php<br />$months = array('2014-01-01','2014-01-02','2014-01-22','2014-02-22','2014-02-26','2014-03-03','2014-03-25','2014-03-28');<br /><br />month_min_day($months);<br /><br />month_days($months);<br /><br />function month_min_day($months){<br />    $tmp = array();<br />    foreach($months as $month){<br />        $key = date('Y-m',strtotime($month));<br />        if(!isset($tmp[$key]) <br><font color='#FF8000'>------解决方案--------------------</font><br> strtotime($month)<$tmp[$key]){<br />            $tmp[$key] = strtotime($month);<br />        }<br />    }<br />    foreach($tmp as $key=>$val){<br />        echo date('Y-m-d',$val).'<br>';<br />    }<br />}<br /><br />function month_days($months){<br />    $tmp = array();<br />    foreach($months as $month){<br />        $key = date('Y-m',strtotime($month));<br />        isset($tmp[$key])? $tmp[$key]++ : $tmp[$key]=1;<br />    }<br />    foreach($tmp as $key=>$val){<br />        echo $key.'->'.$val.'<br>';<br />    }<br />}<br />?><br />