## 问题：如何在python中将列表另存为numpy数组？

Is possible to construct a NumPy array from a python list?

## 回答 0

import numpy as np
a = np.array( [2,3,4] )

import numpy as np
a = np.array( [[2,3,4], [3,4,5]] )

First of all, I’d recommend you to go through NumPy’s Quickstart tutorial, which will probably help with these basic questions.

You can directly create an array from a list as:

import numpy as np
a = np.array( [2,3,4] )

Or from a from a nested list in the same way:

import numpy as np
a = np.array( [[2,3,4], [3,4,5]] )

## 回答 1

from numpy  import array
a = array( your_list )

you mean something like this ?

from numpy  import array
a = array( your_list )

## 回答 2

a = numpy.array([1,2,3])

Yes it is:

a = numpy.array([1,2,3])

## 回答 3

import numpy as np

myList = [1, 2, 3]

np.array(myList).dump(open('array.npy', 'wb'))

…然后阅读：

You want to save it as a file?

import numpy as np

myList = [1, 2, 3]

np.array(myList).dump(open('array.npy', 'wb'))

## 回答 4

>>> a = [1, 2]
>>> np.asarray(a)
array([1, 2])

You can use numpy.asarray, for example to convert a list into an array:

>>> a = [1, 2]
>>> np.asarray(a)
array([1, 2])

## 回答 5

import numpy as np

# b is some list, then ...
a = np.array(b).reshape(lengthDim0, lengthDim1);

I suppose, you mean converting a list into a numpy array? Then,

import numpy as np

# b is some list, then ...
a = np.array(b).reshape(lengthDim0, lengthDim1);

gives you a as an array of list b in the shape given in reshape.

## 回答 6

import csv
import numpy as np

with open('filename','rb') as csvfile:
print "Number of records = " + str(len(cdl))

#then later

npcdl = np.array(cdl)

Here is a more complete example:

import csv
import numpy as np

with open('filename','rb') as csvfile:
print "Number of records = " + str(len(cdl))

#then later

npcdl = np.array(cdl)

Hope this helps!!

## 回答 7

import numpy as np

... ## other code

t=[nodel[ nodenext[i][j] ] for j in idx]
#for each link, find the node lables
#t is the list of node labels

t=np.array(t)
import numpy as np

... ## other code

some list comprehension

t=[nodel[ nodenext[i][j] ] for j in idx]
#for each link, find the node lables
#t is the list of node labels

Convert the list to a numpy array using the array method specified in the numpy library.

t=np.array(t)

## 回答 8

import numpy as np
a=[[1,1],[2,2]]
b=np.asarray(a)
print(type(b))

<class 'numpy.ndarray'>

maybe:

import numpy as np
a=[[1,1],[2,2]]
b=np.asarray(a)
print(type(b))

output:

<class 'numpy.ndarray'>