5. PHP - Convert floating point numbers to integers php floating point number comparison php floating point number precision php floating point number format

1. Use forced type conversion

First of all, PHP supports the following data types:

<code><span>1. </span>Integer    (整数)
<span>2. </span>Float      (浮点数)
<span>3. </span>String     (字符串)
<span>4. </span>Boolean    (布尔值)
<span>5. </span>Array      (数组)
<span>6. </span>Object     (对象)</code>

In addition, there are two special types: NULL (empty) and resource (resource).

Note:
1. Variables that have not been assigned a value, have been reset, or are assigned the special value NULL are NULL type variables.
2. Certain built-in functions (such as database functions) will return variables of resource type.

Then you can use forced type conversion similar to C language. For example,

<code><span><?php</span><span>$a</span>=<span>6.66666</span>;
<span>$b</span>=(integer)<span>$a</span>;
<span>echo</span><span>$b</span>;</code>

will output a 6, directly discarding the decimal part

2. Use the float floor (float value) function

rounding method and return no The next integer greater than value, round off the decimal part of value. The type returned by floor() is still float because the range of float values ​​is usually larger than that of integer.

<code>echo <span>floor</span>(<span>4.3</span>);   <span>// 输出4 </span>
echo <span>floor</span>(<span>9.999</span>); <span>// 输出9</span></code>

3. Use float ceil (float value) function

to round to an integer and return the next integer that is not less than value. If value has a decimal part, it will be rounded up. The type returned by ceil() is still float because the range of float values ​​is usually larger than that of integer.

<code>echo <span>ceil</span>(<span>4.3</span>);    <span>// 输出5 </span>
echo <span>ceil</span>(<span>9.999</span>);  <span>// 输出10</span></code>

4. Use the float round (float val [, int precision]) function

to round floating point numbers and return the result of rounding val according to the specified precision precision (the number of digits after the decimal point). precision can also be negative or zero (default).

<code>echo <span>round</span>(<span>3.4</span>);         <span>// 输出3 </span>
echo <span>round</span>(<span>3.5</span>);         <span>// 输出4 </span>
echo <span>round</span>(<span>3.6</span>);         <span>// 输出4 </span>
echo <span>round</span>(<span>3.6</span>, <span>0</span>);      <span>// 输出4 </span>
echo <span>round</span>(<span>1.95583</span>, <span>2</span>);  <span>// 输出1.96 </span>
echo <span>round</span>(<span>1241757</span>, -<span>3</span>); <span>// 输出1242000 </span>
echo <span>round</span>(<span>5.045</span>, <span>2</span>);    <span>// 输出5.04 </span>
echo <span>round</span>(<span>5.055</span>, <span>2</span>);    <span>// 输出5.06</span></code>

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The above has introduced 5. PHP - Convert floating point numbers to integers, including PHP and floating point numbers. I hope it will be helpful to friends who are interested in PHP tutorials.