# ClickHouse 





下面2句话，上一句话可以看看将要删除的数据，下一句话直接删除这些数据。
```sql
select * from cl_grid_fwi_forecast_hourly_data cgffhd  where update_time  = '2021-10-28 22:00:00';
ALTER  table cl_grid_fwi_forecast_hourly_data delete  where update_time  = '2021-10-28 22:00:00';
```

# Mysql 
```sql
DELETE FROM forest_fire_chongli.alg_national_fire_risk_current_hourly_data where data_time='2021-12-23 00:00:00';
```

ClickHouse 数据库 删除表中数据 Mysql 删除数据

Python





```
        norm = np.sqrt(np.sum(emb*emb)+0.00001)
        emb /= norm
```

特征向量归一化 Python

最开始加这几句程序：




```python
from pylab import mpl
mpl.rcParams['font.sans-serif'] = ['FangSong']  # 指定默认字体
mpl.rcParams['axes.unicode_minus'] = False  # 解决保存图像是负号'-'显示为方块的问题
```

matplotlib Pythoh 如何显示中文

截图目标，分析目标的颜色直方图：





```python
import cv2
from matplotlib import pyplot as plt
def show_img(path):
    img = cv2.imread(path)
    b, g, r = img[:, :, 0], img[:, :, 1], img[:, :, 2]
    hist_b = cv2.calcHist([b], [0], None, [256], [0, 256])
    hist_g = cv2.calcHist([g], [0], None, [256], [0, 256])
    hist_r = cv2.calcHist([r], [0], None, [256], [0, 256])
    plt.figure(figsize=(10, 5))
    plt.subplot(121)
    plt.plot(hist_r, color='r', label="r")
    plt.plot(hist_g, color='g', label="g")
    plt.plot(hist_b, color='b', label="b")
    plt.legend()
    img2 = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
    h, s, v = img2[:, :, 0], img2[:, :, 1], img2[:, :, 2]
    hist_h = cv2.calcHist([h], [0], None, [256], [0, 256])
    hist_s = cv2.calcHist([s], [0], None, [256], [0, 256])
    hist_v = cv2.calcHist([v], [0], None, [256], [0, 256])
    plt.subplot(122)
    plt.plot(hist_h, color='r', label="h")
    plt.plot(hist_s, color='g', label="s")
    plt.plot(hist_v, color='b', label="v")
    plt.legend()
    plt.show()
    return hist_r, hist_g, hist_b, hist_h, hist_s, hist_v
r, g, b, h, s, v = show_img("lanse.png")
```

![在这里插入图片描述](/static/img/images/00262.png)


```
import cv2
import numpy as np
from matplotlib import pyplot as plt
img = cv2.imread("1111.jpg")
hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
lower_red = np.array([115, 0, 160])
upper_red = np.array([140, 30, 190])
mask = cv2.inRange(hsv, lower_red, upper_red)
res = cv2.bitwise_and(img, img, mask=mask)
# cv2.imshow('img', img)
cv2.imshow('mask', mask)
cv2.imshow('res', res)
cv2.waitKey(0)
cv2.destroyAllWindows()
```

Opencv 颜色过滤 Python mask 选取颜色 颜色直方图

Python





```
关闭网络代理，关闭VPN .即可。
```

ValueError: check_hostname requires server_hostname

Python





```python
import re
alist = [[1, 2, 3, [4]], [1, [5, [3, 1]]]]
res = list(map(float, re.findall("\d+", str(alist))))
print(res)
```

Python 取出嵌套列表中的数字

Python





```python
import subprocess
f = subprocess.Popen(['tail', '-F', "/var/log/xferlog"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
while True:
    line = f.stdout.readline()
    print(line)
```

Python tail -f 处理 浏览 实时日志

Python





```python
import json
import xmltodict
d = xmltodict.parse("""
   <mydocument has="an attribute">
     <and>
       <many>elements</many>
       <many>more elements</many>
     </and>
     <plus a="complex">
       element as well
     </plus>
   </mydocument>
""")
print(json.dumps(d, indent=4))
xml_res = xmltodict.unparse(d, pretty=True)
print(xml_res)
```

Python xml 转 dict 转 json

参考：





[https://stackoverflow.com/questions/50807744/apply-css-class-to-pandas-dataframe-using-to-html](https://stackoverflow.com/questions/50807744/apply-css-class-to-pandas-dataframe-using-to-html)

Python Pandas html CSS 表单处理

Python





```python
import ctypes
import os
import platform
import sys
def get_free_space_mb(folder):
    """ Return folder/drive
     space (in bytes)
    """
    if platform.system() == 'Windows':
        free_bytes = ctypes.c_ulonglong(0)
        ctypes.windll.kernel32.GetDiskFreeSpaceExW(ctypes.c_wchar_p(folder), None, None, ctypes.pointer(free_bytes))
        return free_bytes.value / 1024 / 1024 / 1024
    else:
        st = os.statvfs(folder)
        return st.f_bavail * st.f_frsize / 1024 / 1024 / 1024.
if __name__ == '__main__':
    print("这个目录剩余空间:", get_free_space_mb("/run/user/1009"), "G")
```

结果：

这个目录剩余空间: 12.574710845947266 G