How to save data array generated by python?-CodePudding

I developed a python code that generates several arrays of data. I want to save these arrays in a specific location on my computer and then import them into another notebook. It's important that, given a matrix saved as "data.csv", I can import caluns or rows from it. For example data[0] or data[0][1] for example.

I've already tried to do it in a way where I save the data as follows:

with open(path   '/data_Sevol.csv', 'w', newline='') as csvfile:
     fieldnames = ['Sevol']
     writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
     writer.writeheader()
     for i in range(len(Sevol)):
         writer.writerow({'Sevol': Sevol[i]})

However, although I can define a variable that receives the matrix, when calling a row or column it goes wrong.

Does anyone know of a more convenient way to save data so that when importing it I can simply call a row, column or element in the usual way (eg data[i][j]).

Thanks for any help.

CodePudding user response：

If you are trying to store dictionary, you can consider using json, this can be done by import json You can dump dictionary into a string, and load them from file very quickly. You can learn about how to use json here: https://www.w3schools.com/python/python_json.asp If you are using csv, the result of open() csv cannot be directly used like a list, you instead need a function to turn it into a nested list so you can use indexing

import csv
def import_csv(path):
    with open(path,"r") as raw_data:
        result = []
        data = csv.reader(raw_data,delimiter=",")
        for row in data:
            result.appendd(row)
        return result

This function takes the path of a csv file (I assume , is the delimiter) and return a nested list for you to use data[i][j]. However take note that the header is also included, so remember to exclude the first row before you iterate the data

I read your comment and wrote these set of function, calling export_csv() will save an array with the datatype, if you use import_csv() it should return a nested list while preserving the datatype. It only work for int, str, float and bool for now:

import csv
def get_type(inp):
    t = str(type(inp))
    return t.split("'")[1][0]
def fix_type(inp):
    t = inp[0]
    if t == "i":
        return int(inp[1:])
    elif t == "s":
        return str(inp[1:])
    elif t == "f":
        return float(inp[1:])
    elif t == "b":
        return bool(inp[1:])
def transform(array):
    result = []
    for row in array:
        tem = []
        for item in row:
            tem.append(get_type(item) str(item))
        result.append(tem)
    return result
def deform(array):
    result = []
    for row in array:
        tem = []
        for item in row:
            tem.append(fix_type(item))
        result.append(tem)
    return result
def import_csv(path):
    with open(path,"r") as raw_data:
        result = []
        data = csv.reader(raw_data,delimiter=",")
        for row in data:
            result.append(row)
        return deform(result)
def export_csv(path,data):
    with open(path, 'w', newline='') as csvfile:
        writer = csv.writer(csvfile)
        for i in transform(data):
            writer.writerow(i)