php - Return number of lines from a string base on a character -

In PHP, how do I return 6th or 5th or 4th rows from the string that looks like below? Add a new row to the four & lt; Br / & gt; .

Therefore, if I have such a string

  $ lines = 4; $ Song = 'line1 & lt; Br / & gt; Line 2 & lt; Br / & gt; Line 3 & lt; Br / & gt; & Lt; Br / & gt; Line 5 & lt; Br / & gt; Line 6 & lt; Br / & gt; Line 7 & lt; Br / & gt; Line 8 ';  

It should be returned

  line1 & lt; Br / & gt; Line 2 & lt; Br / & gt; Line 3 & lt; Br / & gt; Line 4  

if I have

  $ lines = 4; $ Song = 'line1 & lt; Br / & gt; Line 2 ';  

It should be returned

  line1 & lt; Br / & gt; Line 2  

By dividing the string into an array, before the first array created < Em> n to get the element. Finally join them again.

  $ n = 4; $ Song = 'line1 & lt; Br / & gt; Line 2 & lt; Br / & gt; Line 3 & lt; Br / & gt; & Lt; Br / & gt; Line 5 & lt; Br / & gt; Line 6 & lt; Br / & gt; Line 7 & lt; Br / & gt; Line 8 '; $ Rows = explosion ('& lt; br / & gt;', $ song); Echo Flat ('& lt; br / & gt;', array_slice ($ rows, 0, $ n));