# numpy.lib.scimath.log10¶

`lib.scimath.``log10`(x)[source]

Compute the logarithm base 10 of x.

Return the “principal value” (for a description of this, see `numpy.log10`) of . For real x > 0, this is a real number (`log10(0)` returns `-inf` and `log10(np.inf)` returns `inf`). Otherwise, the complex principle value is returned.

Parameters
xarray_like or scalar

The value(s) whose log base 10 is (are) required.

Returns
outndarray or scalar

The log base 10 of the x value(s). If x was a scalar, so is out, otherwise an array object is returned.

Notes

For a log10() that returns `NAN` when real x < 0, use `numpy.log10` (note, however, that otherwise `numpy.log10` and this `log10` are identical, i.e., both return `-inf` for x = 0, `inf` for x = inf, and, notably, the complex principle value if `x.imag != 0`).

Examples

(We set the printing precision so the example can be auto-tested)

```>>> np.set_printoptions(precision=4)
```
```>>> np.emath.log10(10**1)
1.0
```
```>>> np.emath.log10([-10**1, -10**2, 10**2])
array([1.+1.3644j, 2.+1.3644j, 2.+0.j    ])
```