numpy.arange

numpy.arange([start, ]stop, [step, ]dtype=None)

Return evenly spaced values within a given interval.

Values are generated within the half-open interval [start, stop) (in other words, the interval including start but excluding stop). For integer arguments the function is equivalent to the Python built-in range function, but returns an ndarray rather than a list.

When using a non-integer step, such as 0.1, the results will often not be consistent. It is better to use numpy.linspace for these cases.

Parameters：

• start number, optional.Start of interval. The interval includes this value. The default start value is 0.
• stop number.End of interval. The interval does not include this value, except in some cases where step is not an integer and floating point round-off affects the length of out.
• step number, optional.Spacing between values. For any output out, this is the distance between two adjacent values, out[i+1] - out[i]. The default step size is 1. If step is specified as a position argument, start must also be given.
• dtype dtype.The type of the output array. If dtype is not given, infer the data type from the other input arguments.

Returns：

• arange ndarray

Array of evenly spaced values.

For floating point arguments, the length of the result is ceil((stop - start)/step). Because of floating point overflow, this rule may result in the last element of out being greater than stop.

See also

numpy.linspace

Evenly spaced numbers with careful handling of endpoints.

numpy.ogrid

Arrays of evenly spaced numbers in N-dimensions.

numpy.mgrid

Grid-shaped arrays of evenly spaced numbers in N-dimensions.

Examples

>>> np.arange(3)
array([0, 1, 2])
>>> np.arange(3.0)
array([ 0.,  1.,  2.])
>>> np.arange(3,7)
array([3, 4, 5, 6])
>>> np.arange(3,7,2)
array([3, 5])