I'm writing a python function to append data to text file, as shown in the following,

The problem is the variable, var, could be a 1D numpy array, a 1D list, or just a float number, I know how to convert numpy.array/list/float to string separately (meaning given the type), but is there a method to convert var to string without knowing its type?

def append_txt(filename, var):my_str = _____    # convert var to stringwith open(filename,'a') as f:f.write(my_str + '\n')

Edit 1: Thanks for the comments, sorry maybe my question was not clear enough. str(var) on numpy would give something like []. For example, var = np.ones((1,3)), str(var) will give [[1. 1. 1.]], and [] is unwanted,

Edit 2: Since I want to write clean numbers (meaning no [ or ]), it seems type checking is inevitable.

Type checking is not the only option to do what you want, but definitely one of the easiest:

import numpy as npdef to_str(var):if type(var) is list:return str(var)[1:-1] # listif type(var) is np.ndarray:try:return str(list(var[0]))[1:-1] # numpy 1D arrayexcept TypeError:return str(list(var))[1:-1] # numpy sequencereturn str(var) # everything else

EDIT: Another easy way, which does not use type checking (thanks to jtaylor for giving me that idea), is to convert everything into the same type (np.array) and then convert it to a string:

import numpy as npdef to_str(var):return str(list(np.reshape(np.asarray(var), (1, np.size(var)))[0]))[1:-1]

Example use (both methods give same results):

>>> to_str(1.) #float
'1.0'
>>> to_str([1., 1., 1.]) #list
'1.0, 1.0, 1.0'
>>> to_str(np.ones((1,3))) #np.array
'1.0, 1.0, 1.0'