服务器之家

服务器之家 > 正文

Numpy(Pandas)删除全为零的列的方法

时间:2020-09-12 00:01     来源/作者:SongpingWang

在处理numpy数组,有这个需求,故写下此文:

使用np.argwhere和np.all来查找索引。要使用np.delete删除它们。

示例1

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
import numpy as np
a = np.array([[1, 2, 0, 3, 0],
       [4, 5, 0, 6, 0],
       [7, 8, 0, 9, 0]])
 
idx = np.argwhere(np.all(a[..., :] == 0, axis=0))
a2 = np.delete(a, idx, axis=1)
 
print(a2)
 
"""
[[1 2 3]
 [4 5 6]
 [7 8 9]]
"""

示例2

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
import numpy as np
 
array1 = np.array([[1,0,1,0,0,0,0,0,0,1,1,0,0,0,1,1,0,1,0,0],
          [0,1,1,0,0,1,1,1,1,0,0,0,1,0,1,0,0,1,1,1],
          [0,0,1,0,0,1,1,1,0,0,0,0,0,0,0,1,0,0,1,1],
          [0,1,1,0,0,1,1,1,1,0,1,1,1,0,0,1,0,0,1,1],
          [0,0,1,0,0,1,1,1,0,1,0,1,1,0,1,1,0,0,1,0],
          [1,0,1,0,0,0,1,0,0,1,1,1,1,0,1,1,0,0,1,0],
          [1,0,1,0,1,1,0,0,0,0,1,0,0,0,1,0,0,0,1,1],
          [0,1,0,0,1,0,0,0,1,0,1,1,1,0,1,0,0,1,1,0],
          [0,1,0,0,1,0,0,1,1,0,1,1,1,0,0,1,0,1,0,0],
          [1,0,0,0,0,1,0,1,0,0,0,1,1,0,0,1,0,1,0,0]])
 
mask = (array1 == 0).all(0)
column_indices = np.where(mask)[0]
array1 = array1[:,~mask]
 
print("raw array", array1.shape)  # raw array (10, 20)
print("after array",array1.shape) # after array (10, 17)
print("=====x=====\n",array1)

其它查看:https://moonbooks.org/Articles/How-to-remove-array-rows-that-contain-only-0-in-python/

pandas 删除全零

?
1
2
3
4
5
6
from pandas import DataFrame
 
df1=DataFrame(np.arange(16).reshape((4,4)),index=['a','b','c','d'],columns=['one','two','three','four'])   # 创建一个dataframe
df1.loc['e'] = 0          # 优雅地增加一行全0
df1.ix[(df1==0).all(axis=1), :]  # 找到它
df1.ix[~(df1==0).all(axis=1), :]  # 删了它

到此这篇关于Numpy(Pandas)删除全为零的列的方法的文章就介绍到这了,更多相关Numpy删除全为零的列内容请搜索服务器之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持服务器之家!

原文链接:https://blog.csdn.net/wsp_1138886114/article/details/108450410

标签:

相关文章

热门资讯

2020微信伤感网名听哭了 让对方看到心疼的伤感网名大全
2020微信伤感网名听哭了 让对方看到心疼的伤感网名大全 2019-12-26
Intellij idea2020永久破解,亲测可用!!!
Intellij idea2020永久破解,亲测可用!!! 2020-07-29
歪歪漫画vip账号共享2020_yy漫画免费账号密码共享
歪歪漫画vip账号共享2020_yy漫画免费账号密码共享 2020-04-07
电视剧《琉璃》全集在线观看 琉璃美人煞1-59集免费观看地址
电视剧《琉璃》全集在线观看 琉璃美人煞1-59集免费观看地址 2020-08-12
最新idea2020注册码永久激活(激活到2100年)
最新idea2020注册码永久激活(激活到2100年) 2020-07-29
返回顶部