所以我想对一个列表进行循环计算,但没有成功。我想要一个包含(1+log10(i))
的新列表:
l = [115, 10, 2, 0]
for i in l:
l_1 = []
if i == 0:
l_1.append(i)
else:
l_1.append(1+np.log10(i))
print(l_1)
[0]
答案 0 :(得分:2)
您将在每个循环遍历中创建一个新列表,只需将其取出:
mysqli.allow_local_infile = On
做到这一点的pythonic方法将是一种理解:
l = [115, 10, 2, 0]
l_1 = []
for i in l:
if i == 0:
l_1.append(i)
else:
l_1.append(1+np.log10(i))
答案 1 :(得分:0)
或者您可以充分利用numpy的优势:
import numpy as np
import matplotlib.pyplot as plt
from PIL import Image, ImageSequence
## downloaded from here:
# https://media.giphy.com/media/uQCxA7u9CEdIA/200w_d.gif
img = Image.open("/path/to/Downloads/brainscan.gif")
frames = np.array([np.array(frame.copy().convert('RGB').getdata(),dtype=np.uint8).reshape(frame.size[1],frame.size[0],3) for frame in ImageSequence.Iterator(img)])
print(np.shape(frames))
frame_index=1
fig,axes=plt.subplots(2,4,figsize=(10,4))
axes[0,0].imshow(frames[frame_index,:,:,0],cmap="Reds_r")
axes[0,1].imshow(frames[frame_index,:,:,1],cmap="Greens_r")
axes[0,2].imshow(frames[frame_index,:,:,2],cmap="Blues_r")
axes[0,3].imshow(frames[frame_index,:,:,:],cmap="viridis")
my_slice= frames[frame_index,50:150,100:120,1]
print(np.shape(my_slice[:]))
frames[frame_index,50:150,100:120,1]=0.1*my_slice
axes[1,0].imshow(frames[frame_index,:,:,0],cmap="Reds_r")
axes[1,1].imshow(frames[frame_index,:,:,1],cmap="Greens_r")
axes[1,2].imshow(frames[frame_index,:,:,2],cmap="Blues_r")
axes[1,3].imshow(frames[frame_index,:,:,:],cmap="viridis")
plt.show()
使用numpy.where
清除import numpy as np
l = np.array((115, 10, 2, 0))
r = 1 + np.log10(np.where(l != 0, l, 0.1))
# [ 3.06069784 2. 1.30103 0. ]
(并用0
替换,使得0.1
将在{{1}之后产生np.log10(x) = 1
}。
答案 2 :(得分:0)
这里的问题是data = [item.text for item in soup.select('[offerid]')]
给您i中的值而不是索引,因此您只添加一个值,即最后一个。
这是您想要执行的列表理解:
for i in l