[FIXED] can not convert string to float sklearn

Issue

I wrote this program, but i get error:

ValueError: could not convert string to float

My code:

import sqlite3
from sklearn import tree


database = sqlite3.connect("database.db")
c = database.cursor()

x = []
y = []

for row in c.execute('SELECT * FROM cars'):
    x.append(row[0])
    y.append(row[1])

clf = tree.DecisionTreeClassifier()
ml = clf.fit(x,y)

edit: I read this link (https://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.LabelEncoder.html) but i do not know how to use label encoder in this app - please help me to use label encoder or solve this problem

Solution

An example how to use LabelEncoder properly:

I created a y list which contains some strings:

dummy_y = ['label1', 'label1', 'label2', 'label3', 'label77']

We want to encode each element in the list to a numeric value, LabelEncoder maps each string value to a corresponding numerical value.

First import the LabelEncoder class & create an instance of it:

from sklearn.preprocessing import LabelEncoder
le = LabelEncoder()

Now we can fit_transform our dummy list which means that the instance will first map each string to a value with fit and then will actually apply it with transform:

encoded_dummy_y = le.fit_transform(dummy_y)

will return:

array([0, 0, 1, 2, 3])

Where 0 corresponds to label1, 1 to label2 etc.

Answered By - ImSo3K