在python中向矩阵添加列
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Adding columns to matrix in python
提问by
Is there some way in python to add columns into a matrix.I want to add a column in the beginning of my mxnmatrix in python.Say for example,I have 1000x100matrix and I want to make it into 1000x101matrix. I want to insert new column having all onesin the beginning i.e. it will be my new first column. Is it possible in python?
python中是否有某种方法可以将列添加到矩阵中。我想在python中的矩阵的开头添加一列。mxn比如说，我有1000x100矩阵，我想把它变成1000x101矩阵。我想插入一ones开始就包含所有内容的新列，即它将成为我新的第一列。在python中可能吗？
Here is my code-
vector1is a list, cntis 1000
这是我的代码 -
vector1是一个列表，cnt是 1000
data=np.array(vector1)
shape = ( cnt, 100 )
data=data.reshape(shape)
Now to this I want to add a new column at beginning with all ones
现在，我想在所有列开头添加一个新列
采纳答案by YuppieNetworking
The function you are looking for in numpy.hstackand numpy.ones:
您正在寻找的功能numpy.hstack和numpy.ones：
For example,
例如，
import numpy as np
X = np.random.uniform(size=(10,3))
n,m = X.shape # for generality
X0 = np.ones((n,1))
Xnew = np.hstack((X,X0))
print(X)
[[ 0.78614426 0.24150772 0.94330932]
[ 0.60088812 0.20427371 0.19453546]
[ 0.31853252 0.31669057 0.82782995]
[ 0.71749368 0.54609844 0.74924888]
[ 0.86883981 0.54634575 0.83232409]
[ 0.89313181 0.8006561 0.05072146]
[ 0.79492088 0.07750024 0.45762175]
[ 0.92350837 0.20587178 0.76987197]
[ 0.0092076 0.0044617 0.04673518]
[ 0.69569363 0.3315923 0.15093861]]
print(X0)
[[ 1.]
[ 1.]
[ 1.]
[ 1.]
[ 1.]
[ 1.]
[ 1.]
[ 1.]
[ 1.]
[ 1.]]
print(Xnew)
[[ 0.78614426 0.24150772 0.94330932 1. ]
[ 0.60088812 0.20427371 0.19453546 1. ]
[ 0.31853252 0.31669057 0.82782995 1. ]
[ 0.71749368 0.54609844 0.74924888 1. ]
[ 0.86883981 0.54634575 0.83232409 1. ]
[ 0.89313181 0.8006561 0.05072146 1. ]
[ 0.79492088 0.07750024 0.45762175 1. ]
[ 0.92350837 0.20587178 0.76987197 1. ]
[ 0.0092076 0.0044617 0.04673518 1. ]
[ 0.69569363 0.3315923 0.15093861 1. ]]
回答by Sukesh Kaul
I found the numpy.c_function pretty handy at adding a column to an matrix.
The following code would add a column with all zeros to the matrix.
我发现该numpy.c_函数在向矩阵中添加一列时非常方便。以下代码将向矩阵添加一个全为零的列。
import numpy as np
np.c_[np.ones((100,1)),X]
Here, Xis the original matrix.
这里，X是原始矩阵。
回答by Navin Shrinivas
data=np.loadtxt('ex1data1.txt',delimiter=',')
X=data[:,0]
Y=data[:,1]
X=(np.column_stack((np.ones(np.size(X)),X)))
printing x gives
打印 x 给出
[[ 1. 6.1101]
[ 1. 5.5277]
[ 1. 8.5186]
[ 1. 7.0032]
[ 1. 5.8598]
[ 1. 8.3829]
[ 1. 7.4764]
[ 1. 8.5781]
[ 1. 6.4862]
[ 1. 5.0546]
[ 1. 5.7107]
[ 1. 14.164 ]
[ 1. 5.734 ]
[ 1. 8.4084]
[ 1. 5.6407]
[ 1. 5.3794]
[ 1. 6.3654]
[ 1. 5.1301]
[ 1. 6.4296]
[ 1. 7.0708]
[ 1. 6.1891]
[ 1. 20.27 ]
[ 1. 5.4901]
[ 1. 6.3261]
[ 1. 5.5649]
[ 1. 18.945 ]
[ 1. 12.828 ]
[ 1. 10.957 ]
[ 1. 13.176 ]
[ 1. 22.203 ]
[ 1. 5.2524]
[ 1. 6.5894]
[ 1. 9.2482]
[ 1. 5.8918]
[ 1. 8.2111]
[ 1. 7.9334]
[ 1. 8.0959]
[ 1. 5.6063]
[ 1. 12.836 ]
[ 1. 6.3534]
[ 1. 5.4069]
[ 1. 6.8825]
[ 1. 11.708 ]
[ 1. 5.7737]
[ 1. 7.8247]
[ 1. 7.0931]
[ 1. 5.0702]
[ 1. 5.8014]
[ 1. 11.7 ]
[ 1. 5.5416]
[ 1. 7.5402]
[ 1. 5.3077]
[ 1. 7.4239]
[ 1. 7.6031]
[ 1. 6.3328]
[ 1. 6.3589]
[ 1. 6.2742]
[ 1. 5.6397]
[ 1. 9.3102]
[ 1. 9.4536]
[ 1. 8.8254]
[ 1. 5.1793]
[ 1. 21.279 ]
[ 1. 14.908 ]
[ 1. 18.959 ]
[ 1. 7.2182]
[ 1. 8.2951]
[ 1. 10.236 ]
[ 1. 5.4994]
[ 1. 20.341 ]
[ 1. 10.136 ]
[ 1. 7.3345]
[ 1. 6.0062]
[ 1. 7.2259]
[ 1. 5.0269]
[ 1. 6.5479]
[ 1. 7.5386]
[ 1. 5.0365]
[ 1. 10.274 ]
[ 1. 5.1077]
[ 1. 5.7292]
[ 1. 5.1884]
[ 1. 6.3557]
[ 1. 9.7687]
[ 1. 6.5159]
[ 1. 8.5172]
[ 1. 9.1802]
[ 1. 6.002 ]
[ 1. 5.5204]
[ 1. 5.0594]
[ 1. 5.7077]
[ 1. 7.6366]
[ 1. 5.8707]
[ 1. 5.3054]
[ 1. 8.2934]
[ 1. 13.394 ]
[ 1. 5.4369]]
I found column_stack working flawlessly...hope it helps
我发现 column_stack 工作完美......希望它有帮助
