Convert string to complex valued numpy array

Question

I have a string

s = "[0. -0.002j,-0.002-0.002j,-0.003+0.j ],\n[0.01+0.j , 0.001-0.001j,-0. +0.0009j]]"

And I'd like to convet this to np.array. Using np.fromstring np.loadtxt and using JSON as an intermediate step all have problems with complex numbers (and it's even worse with comma separation.

This type of output is generated by np.array2string(x,separator=',').

What would be elegant/concise/canonical way of doing this conversion?

Initial missing bracket is a typo, keeping original statement of the question so that answers make more sense.

Generating the string with repr(x.tolist()) would be safer. Better yet a pickle.dumps. — hpaulj
– hpaulj, Commented Dec 11, 2019 at 13:09

ForceBru · Accepted Answer · 2019-12-11 12:46:04Z

4

If you fix the missing leading bracket, you can treat this as a regular list with the ast built-in module:

>>> import ast
>>> s = "[[0. -0.002j,-0.002-0.002j,-0.003+0.j ],\n[0.01+0.j , 0.001-0.001j,-0. +0.0009j]]"
>>> ast.literal_eval(s)
[[-0.002j, (-0.002-0.002j), (-0.003+0j)], [(0.01+0j), (0.001-0.001j), 0.0009j]]
>>> import numpy as np
>>> np.array(ast.literal_eval(s))
array([[ 0.   -0.002j , -0.002-0.002j , -0.003+0.j    ],
       [ 0.01 +0.j    ,  0.001-0.001j ,  0.   +0.0009j]])

answered Dec 11, 2019 at 12:46

ForceBru

45k10 gold badges71 silver badges104 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Convert string to complex valued numpy array

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related