CODEWITHSUNDEEP
pythoncsvnumpy
gian9
gian9

Reputation: 107

Read complex numbers from a csv file using python

I am having problem reading complex number from a csv file. The format of the file is the following: 

( -353.10438 +j1.72317617 ),( -23.16000 +j0.72512251 )

I tried importing the data using numpy.genfromtxt: 

data=genfromtxt(fname, dtype=complex, skip_header=10, skip_footer=212, delimiter=',')

But every time I have a complex entry it returns me nan+0.j. I also tried removing the brackets before and after the number, and replacing the j with 1j* but it didn't work.

Any suggestions? Thanks

Upvotes: 4

Views: 3066

Answers (2)

rammelmueller
rammelmueller

Reputation: 1118

You can use 

np.complex(str(a).replace('j', '') + 'j'

to first cast to a string, then shift the 'j' and cast back to a complex number.

Upvotes: 3

Bill Bell
Bill Bell

Reputation: 21643

I moved each 'j' to the position immediately behind the imaginary part of the complex number and squeezed out all the blanks to get a sample file like this.

(-353.10438+1.72317617j),(-23.16000+0.72512251j)
(-353.10438+1.72317617j),(-23.16000+0.72512251j)
(-353.10438+1.72317617j),(-23.16000+0.72512251j)
(-353.10438+1.72317617j),(-23.16000+0.72512251j)

Then I ran code similar to yours with a result similar to what follows.

>>> np.genfromtxt('fname.txt', dtype=complex, delimiter=',')
array([[-353.10438+1.72317617j,  -23.16000+0.72512251j],
       [-353.10438+1.72317617j,  -23.16000+0.72512251j],
       [-353.10438+1.72317617j,  -23.16000+0.72512251j],
       [-353.10438+1.72317617j,  -23.16000+0.72512251j]])

I don't know exactly what you might have to do to get similar results, if indeed this approach will work for you at all.

Best of luck!

Upvotes: 5

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