np.median(d_sorted)函数的作用
时间: 2024-04-13 07:25:55 浏览: 14
`np.median(d_sorted)` 是 NumPy 库中的一个函数,用于计算给定数组的中位数。
中位数是一组数据中的中间值,将数据按升序排列后,位于中间位置的数值即为中位数。如果数据有奇数个,中位数就是中间的数值;如果数据有偶数个,中位数是中间两个数的平均值。
在你的代码中,`d_sorted` 是一个已经按升序排列的数组,`np.median(d_sorted)` 会返回这个数组的中位数。
相关问题
import numpy as np def parsecct(filepath): content = '' d = [] d_sorted = [] with open(filepath, "r") as f: lines = f.readlines() for line in lines: if (len(line.split()) == 4): (flowid1, flowid2, flowid3, cct) = line.split() d.append(int(cct)) d_sorted = sorted(d) content = '{}{}'.format(content, '\naverage CCT: {} total:{}\n'.format(np.mean(d_sorted), len(d_sorted))) content = '{}{}'.format(content, 'medium CCT: {}\n'.format(np.median(d_sorted))) content = '{}{}'.format(content, '95 CCT: {}\n'.format(np.percentile(d_sorted, 95))) content = '{}{}'.format(content, '99 CCT: {}\n'.format(np.percentile(d_sorted, 99))) content = '{}{}'.format(content, '99.9 CCT: {}\n'.format(np.percentile(d_sorted, 99.9))) if __name__ == '__main__': enable_cctpath = "./case10/enable/qp_complete_0.txt" disable_cctpath = "./case10/disable/qp_complete_0.txt" parsecct(enable_cctpath)这一段有什么代码错误
在这段代码中,我注意到一些缩进错误,这可能导致 TabError。确保在整个代码块中使用一致的缩进。另外,你定义了一个函数 `parsecct()`,但是在主程序中调用了这个函数却没有打印或者返回结果。这可能导致你没有看到任何输出。
以下是修复过的代码:
```python
import numpy as np
def parsecct(filepath):
content = ''
d = []
d_sorted = []
with open(filepath, "r") as f:
lines = f.readlines()
for line in lines:
if len(line.split()) == 4:
(flowid1, flowid2, flowid3, cct) = line.split()
d.append(int(cct))
d_sorted = sorted(d)
content = '{}{}'.format(content, '\naverage CCT: {} total:{}\n'.format(np.mean(d_sorted), len(d_sorted)))
content = '{}{}'.format(content, 'medium CCT: {}\n'.format(np.median(d_sorted)))
content = '{}{}'.format(content, '95 CCT: {}\n'.format(np.percentile(d_sorted, 95)))
content = '{}{}'.format(content, '99 CCT: {}\n'.format(np.percentile(d_sorted, 99)))
content = '{}{}'.format(content, '99.9 CCT: {}\n'.format(np.percentile(d_sorted, 99.9)))
return content
if __name__ == '__main__':
enable_cctpath = "./case10/enable/qp_complete_0.txt"
disable_cctpath = "./case10/disable/qp_complete_0.txt"
result_enable = parsecct(enable_cctpath)
result_disable = parsecct(disable_cctpath)
print("Enable Results:")
print(result_enable)
print("Disable Results:")
print(result_disable)
```
这样你就能在主程序中调用 `parsecct()` 函数,并打印函数的结果。
def median_filter(img, kernel_size): """中值滤波器""" kernel_half = kernel_size // 2 img_median = np.zeros_like(img) # 对每个像素进行中值滤波 for i in range(kernel_half, img.shape[0] - kernel_half): for j in range(kernel_half, img.shape[1] - kernel_half): # 获取当前像素周围的像素值 neighbors = img[ i - kernel_half: i + kernel_half + 1, j - kernel_half: j + kernel_half + 1 ] # 对这些像素值进行排序 sorted_neighbors = np.sort(neighbors.flatten()) # 取中间的值作为当前像素的值 img_median[i, j] = sorted_neighbors[kernel_half] return img_median优化一下这个代码
可以使用`np.lib.stride_tricks.as_strided()`函数来实现更高效的中值滤波器。以下是优化后的代码:
```
def median_filter(img, kernel_size):
"""中值滤波器"""
kernel_half = kernel_size // 2
img_median = np.zeros_like(img)
# 构建移动窗口
shape = (img.shape[0] - kernel_size + 1,
img.shape[1] - kernel_size + 1,
kernel_size,
kernel_size)
strides = (img.strides[0],
img.strides[1],
img.strides[0],
img.strides[1])
windows = np.lib.stride_tricks.as_strided(img,
shape=shape,
strides=strides)
# 对每个窗口进行中值滤波
medians = np.median(windows, axis=(2,3))
# 将中值赋值给输出图像
img_median[kernel_half:img.shape[0] - kernel_half,
kernel_half:img.shape[1] - kernel_half] = medians
return img_median
```
这个优化后的中值滤波器函数使用了`np.lib.stride_tricks.as_strided()`函数来构建移动窗口,然后使用`np.median()`函数来计算每个窗口的中值。这种方法比原来的双重循环更高效,因为它只需要遍历每个窗口一次。