TypeError only length-1 arrays can be converted to Python scalars while trying to exponentially fit data

Question

f np loadtxt  Single Small Angle 1 txt  unpack True skiprows 2  g np loadtxt  Single Small Angle 5 txt  unpack True skiprows 2   x   f-g    11944  t range len x   m math log10 abs x    np polyfit t m   plt plot t abs x   plt show     I m just not sure on how to fix my issue  It keeps saying   m math log10 abs x   TypeError  only length-1 arrays can be converted to Python scalars

User · Answer

Non-numpy functions like math abs   or math log10   don t play nicely with numpy arrays  Just replace the line raising an error with   m   np log10 np abs x     Apart from that the np polyfit   call will not work because it is missing a parameter  and you are not assigning the result for further use anyway

User · Answer

Here is another way to reproduce this error in Python2 7 with numpy   import numpy as np a   np array  1 2 3   b   np array  4 5 6   c   np concatenate a b     note the lack of tuple format for a and b print c     The np concatenate method produces an error   TypeError  only length-1 arrays can be converted to Python scalars   If you read the documentation around numpy concatenate  then you see it expects a tuple of numpy array objects   So surrounding the variables with parens fixed it   import numpy as np a   np array  1 2 3   b   np array  4 5 6   c   np concatenate  a b     surround a and b with parens  packaging them as a tuple print c     Then it prints    1 2 3 4 5 6    What s going on here   That error is a case of bubble-up implementation - it is caused by duck-typing philosophy of python   This is a cryptic low-level error python guts puke up when it receives some unexpected variable types  tries to run off and do something  gets part way through  the pukes  attempts remedial action  fails  then tells you that  you can t reformulate the subspace responders when the wind blows from the east on Tuesday      In more sensible languages like C   or Java  it would have told you   you can t use a TypeA where TypeB was expected    But Python does it s best to soldier on  does something undefined  fails  and then hands you back an unhelpful error   The fact we have to be discussing this is one of the reasons I don t like Python  or its duck-typing philosophy

[python] TypeError: only length-1 arrays can be converted to Python scalars while trying to exponentially fit data

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