How to change array of (rounded) floats to array of strings python

Question

I have some arrays of numbers that are rounded to 2 digits, xx.xx (decimals=2, using np.around), that I would like to save to a text document for human reading. I would like to change these 'number' arrays to arrays of strings, so that I can combine them with other arrays of strings (row and column headers) and use numpy.savetxt in order to save my data in a readable way to a text document. How can I change my arrays of 'numbers' to arrays of strings? (I believe the numbers are rounded floats, which should still be float, not sure how to check though)

A=np.array([57/13, 7/5, 6/8])

which yields array([4.384615384615385, 1.4, 0.75 ])

B=A.astype('|S4' )

yields array([b'4.38',b'1.4', b'0.75]). The b's remain when I save to txt.

np.savetxt('my_file.txt', B, fmt="%s)

How do I get rid of the b's?

I know that they talk about the b's here What does the 'b' character do in front of a string literal?, but I don't see how to get rid of it.

Using .astype is not a requirement, just seemed like a good way to do it.

possible duplicate of Numpy converting array from float to strings — paisanco
– paisanco, Commented Jul 22, 2015 at 0:44

Joe Kington · Accepted Answer · 2015-07-22 13:23:22Z

1

In your specific case, it's best to use np.savetxt(fname, data, fmt='%0.2f'), where data is your original floating point array.

The fmt specifier is a sprintf-style format string. %0.2f specifies numbers will be displayed as floats (f -- as opposed to scientific notation) and formatted with as many characters as necessary to the left of the decimal point (the 0) and 2 characters to the right of the decimal point.

For example:

import numpy as np

a = np.array([57./13, 7./5, 6./8])
np.savetxt('out.txt', a, fmt='%0.2f')

And the resulting out.txt file will look like:

4.38
1.40
0.75

answered Jul 22, 2015 at 13:23

Joe Kington

287k73 gold badges621 silver badges474 bronze badges

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

2 Comments

Mark Over a year ago

Thanks, this is helpful; however my output looks like 4.381.400.75 (all in one line with no spaces).

Joe Kington Over a year ago

@Mark - That's because it's a 1D array. If you'd like it to be a 2D column vector, save np.column_stack([your_data]) or your_data[:,None].

Collectives™ on Stack Overflow

How to change array of (rounded) floats to array of strings python

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related