NumPy linspace()
The `numpy.linspace()` function generates an array of evenly spaced values over a specified interval. It is commonly used in numerical computations where a range of values needs to be sampled.
Usage
The `numpy.linspace()` function is employed when you need a specified number of evenly spaced samples between two numbers. It is particularly useful for creating datasets for plotting or numerical analysis.
numpy.linspace(start, stop, num=50, endpoint=True, retstep=False, dtype=None, axis=0)
In this syntax:
start
is the starting value of the sequence.stop
is the end value of the sequence.num
specifies the number of samples to generate. Ifnum
is set to 1, a single value equal tostart
will be returned. Ifnum
is 0, an empty array is returned.endpoint
indicates whether to include thestop
value.retstep
determines if the spacing between values should be returned.dtype
sets the desired data type of the output array.axis
specifies the axis in the result to store the samples. This allows you to insert the generated samples along a specified axis in a multi-dimensional array, rather than the default 1-dimensional output.
Examples
1. Basic Usage
import numpy as np
array = np.linspace(0, 10, num=5)
This generates an array of 5 evenly spaced values starting at 0 and ending at 10: [0. , 2.5, 5. , 7.5, 10.]
.
2. Excluding Endpoint
import numpy as np
array = np.linspace(0, 10, num=5, endpoint=False)
Here, the endpoint=False
parameter is used, resulting in 5 values from 0 to just below 10: [0. , 2. , 4. , 6. , 8.]
.
3. Returning Step Size
import numpy as np
array, step = np.linspace(0, 10, num=5, retstep=True)
This example returns both the array and the step size between values, which is 2.5
in this case.
4. Using Axis Parameter
import numpy as np
array = np.linspace(0, 10, num=5, axis=1)
This creates a 2-dimensional array if combined with another dimension, placing the samples along the second axis.
5. Edge Cases for `num`
num=1
:np.linspace(0, 10, num=1)
produces[0.]
.num=0
:np.linspace(0, 10, num=0)
produces[]
.
Tips and Best Practices
- Specify `num` carefully. Choose a `num` value that adequately represents the range without overwhelming memory.
- Use `endpoint=False` for open intervals. When you don't want to include the stop value, set
endpoint
toFalse
. - Utilize `retstep=True` for step information. If the spacing between values is crucial for further computations, use
retstep=True
. - Consider data type with `dtype`. Specify
dtype
to control the precision of the output array, especially in large computations. - Performance considerations. Be mindful of memory usage and computation time when generating large arrays or when using high precision data types with
dtype
.