is_null

နမူနာ

variable ကို null ရှိမရှိစစ်ဆေးပါ:

 <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 keyword">ပဲ့တင်သံ</span> <span class="token string double-quoted-string">"a"</span> <span class="token operator">။</span> <span class="token function">is_null</span> <span class="token punctuation">(</span> <span class="token variable">$ က</span> <span class="token punctuation">)</span> <span class="token operator">။</span> <span class="token string double-quoted-string">"<br> <br>"</span> <span class="token punctuation">;</span>

<span class="token variable">$ ခ</span> <span class="token operator">=</span> <span class="token constant">null</span> <span class="token punctuation">;</span>
<span class="token keyword">ပဲ့တင်သံ</span> <span class="token string double-quoted-string">"B"</span> <span class="token operator">။</span> <span class="token function">is_null</span> <span class="token punctuation">(</span> <span class="token variable">$ ခ</span> <span class="token punctuation">)</span> <span class="token operator">။</span> <span class="token string double-quoted-string">"<br> <br>"</span> <span class="token punctuation">;</span>

<span class="token variable">$ c</span> <span class="token operator">=</span> <span class="token string double-quoted-string">"null"</span> <span class="token punctuation">;</span>
<span class="token keyword">ပဲ့တင်သံ</span> <span class="token string double-quoted-string">"C သည်" ဖြစ်သည်</span> <span class="token operator">။</span> <span class="token function">is_null</span> <span class="token punctuation">(</span> <span class="token variable">$ ဂ</span> <span class="token punctuation">)</span> <span class="token operator">။</span> <span class="token string double-quoted-string">"<br> <br>"</span> <span class="token punctuation">;</span>

<span class="token variable">$ d</span> <span class="token operator">=</span> <span class="token constant">null</span> <span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token string double-quoted-string">"d is"</span> <span class="token operator">။</span> <span class="token function">is_null</span> <span class="token punctuation">(</span> <span class="token variable">$ d</span> <span class="token punctuation">)</span> <span class="token operator">။</span> <span class="token string double-quoted-string">"<br> <br>"</span> <span class="token punctuation">;</span>
<span class="token delimiter important">></span></span>

သင်ကိုယ်တိုင်စမ်းကြည့်ပါ

ဥပမာရှင်းလင်းချက်:

variable $ a ၏တန်ဖိုးသည် 0 ဖြစ်သည်။ NULL မဟုတ်ပါ, ထို့ကြောင့် is_null ($ က) သည်မှားယွင်းသောအယူမှားသည်။ Variables $ B နှင့် $ d တန်ဖိုးများသည် Null ဖြစ်ပြီး, variable $ c ၏တန်ဖိုးသည် Null မဟုတ်ဘဲ NULL "NULL" ဖြစ်သည်။