How to convert a list of strings to an array? (NOT using NumPy)

Question

I am working on a project with an interface of python and an other program where. I need to import data from an excel file und use the data stored in an array for further use. The data of the excel file is pure text.

So far I managed to convert the data into a list of strings. Now I am struggeling by converting the list to an array, not using numpy. As for this project I am working on an interface which does not work with numpy, that's why I have to use the array module.

Here is the part of the relevant code:

from array import array

data_list = []
for i in ws.values:
    data_list.append(i)
print(data_list)

data_array = array('u', data_list))
print(data_array)

The first lines of code are just working fine. The problem shows up in the line where I want to create the array. Doing this I want to use the variable for the list variable (data_list) for that I don't have to tipe all of the 50+ strings.

data_array = array('u', data_list))

Fere the following error occurs:

TypeError: array item must be unicode character

I could not find a unicode character browsing through the internet. How can I fix this problem? Or is there an other way to convert a list of strings to an array (NOT using NumPy)?

I am also wondering whether 'u' is the correct type to use here.

Answer 1

The error indicates that there are values in the list which are not unicode characters – these might be numbers but also empty strings or strings longer than one character.

>>> import array
>>> array.array("u", "Hello World!")  # string of characters – fine
array('u', 'Hello World!')
>>> array.array("u", ["Hello", "World!"])  # list of strings – error!
TypeError: array item must be unicode character
>>> array.array("u", ["1", "2", "3", "4"]) # list of characters – fine
array('u', '1234')
>>> array.array("u", ["1", 2, 3, "4"])  # list of characters/numbers - error!
TypeError: array item must be unicode character

Convert all values to string. Depending on the expected data format, either create separate arrays per word or str.join all words.

>>> data = ["Hello World!", "Dear", 5]
>>> array.array("u", '\n'.join(str(line) for line in data))
array('u', 'Hello World!\nDear\n5')