# Python – Get the Phase Angle of a Complex Number

In this tutorial, we will look at how to get the phase (or the angle) of a complex number in Python with the help of some examples. The phase (or angle) of a complex number is defined as the angle the complex number vector makes with the real axis in the counter-clockwise direction.

## How to get the phase of a complex number in Python?

You can use the `numpy.angle()` function to get the phase (or the angle) of a complex number in Python. The following is the syntax –

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```# get the angle of complex number - make sure to import numpy
numpy.angle(z, deg=False)```

It returns the angle in radians by default. If you want to get the angle in degrees, pass `deg=True` as an argument to the function.

Note that you can use this function on an array of complex numbers as well. In which case it will return an array of the element-wise angle values for the complex numbers in the array.

## Examples

Let’s now look at some examples of using the `numpy.angle()` function.

### Example 1 – Get the phase of a complex number in radians

By default, the `numpy.angle()` function returns the phase angle in radians.

Let’s apply it to three scalar values – a real number, a complex number with non-zero real and imaginary components, and a complex number with a non-zero imaginary component (an imaginary number).

```import numpy as np

# get the angle of complex number (in radians)
print(np.angle(14))
print(np.angle(1+1j))
print(np.angle(3j))```

Output:

```0.0
0.7853981633974483
1.5707963267948966```

We get the angles for each of the complex numbers in radians.

### Example 2 – Get the phase of a complex number in degrees

To get the phase of a complex number in degrees, pass `deg=True` as an argument to the `numpy.angle()` function.

Let’s use the same three inputs as the above example.

```# get the angle of complex number (in degrees)
print(np.angle(14, deg=True))
print(np.angle(1+1j, deg=True))
print(np.angle(3j, deg=True))```

Output:

```0.0
45.0
90.0```

We get the angles of the complex numbers in degrees.

### Example 3 – Get the phase of an array of complex numbers

You can also apply the `numpy.angle()` function to an array, in which case, it will return a Numpy array of the element-wise phase angles.

Let’s apply this function on a Numpy array.

```# element-wise get the angle in array of complex numbers
ar = np.array([14, 1+1j, 3j])
np.angle(ar, deg=True)```

Output:

`array([ 0., 45., 90.])`

We get the element-wise array of the angles for the values in the `ar` array.

## Summary

In this tutorial, we looked at how we can use the `numpy.angle()` function to get the phase (or angle) of a complex number in Python. The following are the key takeaways from this tutorial.

• The `numpy.angle()` function returns the angle of a complex number in radians by default.
• To get the angle in degrees, pass `deg=True` to the `numpy.angle()` function.
• You can also apply this function on an array, in which case it will return the element-wise angles.

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