isset
변수가 설정되어 있고 null이 아닌지 감지
한국어
한국어
변수가 비어 있는지 확인하십시오. 변수가 설정/선언되었는지 확인하십시오.
<span class="token php language-php"><span class="token delimiter important"><? php</span>
<span class="token variable">$ a</span> <span class="token operator">=</span> <span class="token number">0</span> <span class="token punctuation">;</span>
<span class="token comment">// $ a가 설정되어 있기 때문에 true</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span> <span class="token keyword">isset</span> <span class="token punctuation">(</span> <span class="token variable">$ a</span> <span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span>
<span class="token keyword">echo</span> <span class="token string double-quoted-string">"variable 'a'가 설정되었습니다. <br>"</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token variable">$ b</span> <span class="token operator">=</span> <span class="token constant">null</span> <span class="token punctuation">;</span>
<span class="token comment">// $ b가 null이기 때문에 false</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span> <span class="token keyword">isset</span> <span class="token punctuation">(</span> <span class="token variable">$ b</span> <span class="token punctuation">)</span> <span class="token punctuation">)</span> <span class="token punctuation">{</span>
<span class="token keyword">에코</span> <span class="token string double-quoted-string">"변수 'b'가 설정되었습니다."</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token delimiter important">?></span></span>
strval
is_integer
is_array
get_defined_vars
unset
var_dump
gettype
empty
