Sum of array elements over a given axis. Parameters ---------- a : array_like Elements to sum. axis : None or int or tuple of ints, optional Axis or axes along which a sum is performed. The default, axis=None, will sum all of the elements of the input a
(a, axis=None, dtype=None, out=None, keepdims=np._NoValue,
initial=np._NoValue, where=np._NoValue)
| 2176 | |
| 2177 | @array_function_dispatch(_sum_dispatcher) |
| 2178 | def sum(a, axis=None, dtype=None, out=None, keepdims=np._NoValue, |
| 2179 | initial=np._NoValue, where=np._NoValue): |
| 2180 | """ |
| 2181 | Sum of array elements over a given axis. |
| 2182 | |
| 2183 | Parameters |
| 2184 | ---------- |
| 2185 | a : array_like |
| 2186 | Elements to sum. |
| 2187 | axis : None or int or tuple of ints, optional |
| 2188 | Axis or axes along which a sum is performed. The default, |
| 2189 | axis=None, will sum all of the elements of the input array. If |
| 2190 | axis is negative it counts from the last to the first axis. |
| 2191 | |
| 2192 | .. versionadded:: 1.7.0 |
| 2193 | |
| 2194 | If axis is a tuple of ints, a sum is performed on all of the axes |
| 2195 | specified in the tuple instead of a single axis or all the axes as |
| 2196 | before. |
| 2197 | dtype : dtype, optional |
| 2198 | The type of the returned array and of the accumulator in which the |
| 2199 | elements are summed. The dtype of `a` is used by default unless `a` |
| 2200 | has an integer dtype of less precision than the default platform |
| 2201 | integer. In that case, if `a` is signed then the platform integer |
| 2202 | is used while if `a` is unsigned then an unsigned integer of the |
| 2203 | same precision as the platform integer is used. |
| 2204 | out : ndarray, optional |
| 2205 | Alternative output array in which to place the result. It must have |
| 2206 | the same shape as the expected output, but the type of the output |
| 2207 | values will be cast if necessary. |
| 2208 | keepdims : bool, optional |
| 2209 | If this is set to True, the axes which are reduced are left |
| 2210 | in the result as dimensions with size one. With this option, |
| 2211 | the result will broadcast correctly against the input array. |
| 2212 | |
| 2213 | If the default value is passed, then `keepdims` will not be |
| 2214 | passed through to the `sum` method of sub-classes of |
| 2215 | `ndarray`, however any non-default value will be. If the |
| 2216 | sub-class' method does not implement `keepdims` any |
| 2217 | exceptions will be raised. |
| 2218 | initial : scalar, optional |
| 2219 | Starting value for the sum. See `~numpy.ufunc.reduce` for details. |
| 2220 | |
| 2221 | .. versionadded:: 1.15.0 |
| 2222 | |
| 2223 | where : array_like of bool, optional |
| 2224 | Elements to include in the sum. See `~numpy.ufunc.reduce` for details. |
| 2225 | |
| 2226 | .. versionadded:: 1.17.0 |
| 2227 | |
| 2228 | Returns |
| 2229 | ------- |
| 2230 | sum_along_axis : ndarray |
| 2231 | An array with the same shape as `a`, with the specified |
| 2232 | axis removed. If `a` is a 0-d array, or if `axis` is None, a scalar |
| 2233 | is returned. If an output array is specified, a reference to |
| 2234 | `out` is returned. |
| 2235 |