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2016-08-11 09:02
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PHP - 如何获得API值的一致输出 - 浮点数具有特定的小数位数

My API request currently returns JSON in the following format:

[
  {
    "date":"2016-08-11",
    "voltage":0.1,
    "current":0.01,
    "power":0,
    "energy": null,
  }
]

I'm trying to ensure consistency of data output by forcing the voltage, current and power values to be three decimal places, type float. I've tried using number_format() but the output are type strings, which I do not want. Is there a way of doing this, i.e. outputting 0 as a float 0.000 rather than staying an integer? Also, when no values are present I need to convert null into 0.000, is that possible without casting to strings?

The question PHP float with 2 decimal places: .00 doesn't explain (in layman's terms) why this is not possible in PHP.

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我的API请求当前以下列格式返回JSON:

  [
 {
“date”:“2016-08-11”,
“电压”:0.1,
“当前”:0.01,
“电源”:0,
“能量”:null  ,
} 
] 
   
 
 

我试图通过强制电压,电流和功率值为小数点后三位来确保数据输出的一致性,类型 浮动。 我尝试使用 number_format(),但输出是类型字符串,我不想要。 有没有办法做到这一点,即输出 0 作为float 0.000 而不是保持整数? 此外,当没有值存在时,我需要将null转换为0.000,是否可以不转换为字符串?

问题带有2位小数的PHP浮点数:.00 没有解释(用外行的术语)为什么这在PHP中是不可能的。

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1条回答 默认 最新

  • douqiang1851 2016-08-11 09:06
    已采纳
    echo floatval(number_format('0.001', 3)); // output: float 0.001
    

    But unfortunately strings containing '0.000' or null after type casting will produce 0.

    echo (float)number_format('0.000', 3); // output: 0
    echo floatval(number_format('0.000', 3)); // output: 0
    echo floatval(number_format(null, 3)); // output: 0
    

    "...bytes with value 0 (“NUL bytes”) are allowed anywhere in the string (however, a few functions, said in this manual not to be “binary safe”, may hand off the strings to libraries that ignore data after a NUL byte.)" Details of the String Type

    You may handle output at the presentation layer instead.

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