Reading scientific notation of csv file with numpy

Question

I am trying to load a file representing a 2D matrix with numpy loadtxt

cov = np.loadtxt("cov.csv") 

The first element is in scientific notation, which causes failure

 --------------------------------------------------------------------------- ValueError Traceback (most recent call last) <ipython-input-80-0796abd8c0f7> in <module>() ----> 1 cov = np.loadtxt("cov.csv") C:\home\Anaconda3\lib\site-packages\numpy\lib\npyio.py in loadtxt(fname, dtype, comments, delimiter, converters, skiprows, usecols, unpack, ndmin) 858 859 # Convert each value according to its column and store --> 860 items = [conv(val) for (conv, val) in zip(converters, vals)] 861 # Then pack it according to the dtype nesting 862 items = pack_items(items, packing) C:\home\Anaconda3\lib\site-packages\numpy\lib\npyio.py in <listcomp>(.0) 858 859 # Convert each value according to its column and store --> 860 items = [conv(val) for (conv, val) in zip(converters, vals)] 861 # Then pack it according to the dtype nesting 862 items = pack_items(items, packing) ValueError: could not convert string to float: b'5.0e-7,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0' 

I could not find documentation on how to make this work.

 numpy version: 1.9.2 python version: 3.4.3 |Anaconda 2.3.0 (32-bit)| (default, Mar 6 2015, 12:08:17) [MSC v.1600 32 bit (Intel)] 

Answer 1

It is not scientific notation that the problem; that the default loadtxt is any space. You read csv, so specify delimiter="," :

 >>> np.loadtxt("cov.csv") Traceback (most recent call last): File "<ipython-input-1-6fdfa7467ef5>", line 1, in <module> np.loadtxt("cov.csv") File "/usr/local/lib/python3.4/dist-packages/numpy/lib/npyio.py", line 928, in loadtxt items = [conv(val) for (conv, val) in zip(converters, vals)] File "/usr/local/lib/python3.4/dist-packages/numpy/lib/npyio.py", line 928, in <listcomp> items = [conv(val) for (conv, val) in zip(converters, vals)] File "/usr/local/lib/python3.4/dist-packages/numpy/lib/npyio.py", line 659, in floatconv return float(x) ValueError: could not convert string to float: b'5.0e-7,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0' >>> np.loadtxt("cov.csv", delimiter=",") array([ 5.00000000e-07, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00, 0.00000000e+00])