Php deletes null values or specified values in an array.

We will introduce the operations on arrays in php, delete the specified values in the array, or determine whether there are values in the array or clear null values. If you need such operations, you can refer to them.

First, let's take a look at several methods for php to operate on null values in arrays.

Implode (); this function can refer to http://www.bKjia. c0m/phper/29/2 dc95be9381b4bb1753083c09fda1a36.htm
Use implode () to output the array as a string and determine whether the output string is null. It seems to be a good method at the beginning, but unfortunately it keeps up with 1.1. It won't work for arrays above two dimensions. For example:

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$ Arr = array (), array (), array ()); $ Str = implode (',', $ arr ); If (empty ($ str) echo "null "; Else echo "not empty ";

Obviously, $ arr is a two-dimensional array containing three empty arrays. It should be empty, but the output is indeed non-empty. Failed.
Iii. count (); see http://www.bKjia. c0m/w3school/php/func_array_count.htm

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$ Arr = array ("","",""); Echo count ($ arr );

Iv. in_array ('', $ arr); function usage can refer to http://www.bKjia. c0m/phper/24/c5b81a8af14b1c0928eea343f59b454a.htm

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$ Arr = array ("d", "s ",""); Echo in_array ('', $ arr );

This can only indicate empty elements in the array, and it cannot be proved that the array is empty. Obviously not.
V. empty (); function usage can refer to http://www.bKjia. c0m/so/php + empty ()
This cpyeh is similar to the previous methods.

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$ Arr = array ("","",""); If (empty ($ arr) echo "null "; Else echo "not empty ";

The result is not empty.
6. Use strlen (). If there is no content, it seems that the length is 1.

In combination with the above instance, we will write a complete element to delete null values in the array.

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Function array_remove_key ($ array, $ keys) { $ Num = count ($ keys ); $ Num_last = $ num-1; $ This_array_0 = & $ array; $ Last_key = $ keys [$ num_last]; For ($ I = 0; $ I <$ num_last; $ I ++) { $ This_key = $ keys [$ I]; $ This_var_name = 'this _ array _ '. $ I; $ Next_var_name = 'this _ array _ '. ($ I + 1 ); If (! Array_key_exists ($ this_key, $ this_var_name )){ Break; } $ Next_var_name = & $ {$ this_var_name} [$ this_key]; } Unset ($ {$ next_var_name} [$ last_key]); Return $ array; }