"sklearn.datasets" is a scikit package, where it contains a method load_iris().
load_iris(), by default return an object which holds data, target and other members in it. In order to get actual values you have to read the data and target content itself.
Whereas 'iris.csv', holds feature and target together.
FYI: If you set return_X_y as True in load_iris(), then you will directly get features and target.
from sklearn import datasets
data,target = datasets.load_iris(return_X_y=True)
Answer from vipin bansal on Stack Exchangepyspark - DataFrame' object has no attribute 'get - Stack Overflow
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"sklearn.datasets" is a scikit package, where it contains a method load_iris().
load_iris(), by default return an object which holds data, target and other members in it. In order to get actual values you have to read the data and target content itself.
Whereas 'iris.csv', holds feature and target together.
FYI: If you set return_X_y as True in load_iris(), then you will directly get features and target.
from sklearn import datasets
data,target = datasets.load_iris(return_X_y=True)
The Iris Dataset from Sklearn is in Sklearn's Bunch format:
print(type(iris))
print(iris.keys())
output:
<class 'sklearn.utils.Bunch'>
dict_keys(['data', 'target', 'target_names', 'DESCR', 'feature_names', 'filename'])
So, that's why you can access it as:
x=iris.data
y=iris.target
But when you read the CSV file as DataFrame as mentioned by you:
iris = pd.read_csv('iris.csv',header=None).iloc[:,2:4]
iris.head()
output is:
2 3
0 petal_length petal_width
1 1.4 0.2
2 1.4 0.2
3 1.3 0.2
4 1.5 0.2
Here the column names are '1' and '2'.
First of all you should read the CSV file as:
df = pd.read_csv('iris.csv')
you should not include header=None as your csv file includes the column names i.e. the headers.
So, now what you can do is something like this:
X = df.iloc[:, [2, 3]] # Will give you columns 2 and 3 i.e 'petal_length' and 'petal_width'
y = df.iloc[:, 4] # Label column i.e 'species'
or if you want to use the column names then:
X = df[['petal_length', 'petal_width']]
y = df.iloc['species']
Also, if you want to convert labels from string to numerical format use sklearn LabelEncoder
from sklearn import preprocessing
le = preprocessing.LabelEncoder()
y = le.fit_transform(y)
The syntax you are using is for a pandas DataFrame. To achieve this for a spark DataFrame, you should use the withColumn() method. This works great for a wide range of well defined DataFrame functions, but it's a little more complicated for user defined mapping functions.
General Case
In order to define a udf, you need to specify the output data type. For instance, if you wanted to apply a function my_func that returned a string, you could create a udf as follows:
import pyspark.sql.functions as f
my_udf = f.udf(my_func, StringType())
Then you can use my_udf to create a new column like:
df = df.withColumn('new_column', my_udf(f.col("some_column_name")))
Another option is to use select:
df = df.select("*", my_udf(f.col("some_column_name")).alias("new_column"))
Specific Problem
Using a udf
In your specific case, you want to use a dictionary to translate the values of your DataFrame.
Here is a way to define a udf for this purpose:
some_map_udf = f.udf(lambda x: some_map.get(x, None), IntegerType())
Notice that I used dict.get() because you want your udf to be robust to bad inputs.
df = df.withColumn('new_column', some_map_udf(f.col("some_column_name")))
Using DataFrame functions
Sometimes using a udf is unavoidable, but whenever possible, using DataFrame functions is usually preferred.
Here is one option to do the same thing without using the udf.
The trick is to iterate over the items in some_map to create a list of pyspark.sql.functions.when() functions.
some_map_func = [f.when(f.col("some_column_name") == k, v) for k, v in some_map.items()]
print(some_map_func)
#[Column<CASE WHEN (some_column_name = a) THEN 0 END>,
# Column<CASE WHEN (some_column_name = c) THEN 1 END>,
# Column<CASE WHEN (some_column_name = b) THEN 1 END>]
Now you can use pyspark.sql.functions.coalesce() inside of a select:
df = df.select("*", f.coalesce(*some_map_func).alias("some_column_name"))
This works because when() returns null by default if the condition is not met, and coalesce() will pick the first non-null value it encounters. Since the keys of the map are unique, at most one column will be non-null.
You have a spark dataframe, not a pandas dataframe. To add new column to the spark dataframe:
import pyspark.sql.functions as F
from pyspark.sql.types import IntegerType
df = df.withColumn('new_column', F.udf(some_map.get, IntegerType())(some_column_name))
df.show()
wine = pd.read_csv("combined.csv", header=0).iloc[:-1]
df = pd.DataFrame(wine)
df
dataset = pd.DataFrame(df.data, columns =df.feature_names)
dataset['target']=df.target
datasetERROR:
<ipython-input-27-64122078da92> in <module>
----> 1 dataset = pd.DataFrame(df.data, columns =df.feature_names)
2 dataset['target']=df.target
3 dataset
D:\Anaconda\lib\site-packages\pandas\core\generic.py in __getattr__(self, name)
5463 if self._info_axis._can_hold_identifiers_and_holds_name(name):
5464 return self[name]
-> 5465 return object.__getattribute__(self, name)
5466
5467 def __setattr__(self, name: str, value) -> None:
AttributeError: 'DataFrame' object has no attribute 'data'I'm trying to set up a target to proceed with my Multi Linear Regression Project, but I can't even do that. I've already downloaded the CSV file and have it uploaded on a Jupyter Notebook. What I'm I doing wrong?
You tried to use .Values with a capital v instead of .values. Changing the capital v to a lowercase v should solve fix the error you're getting.
Pandas dataframe object does not have any var as Values, rather it is values with small "v". For further reference you can refer pandas documentation -
https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.values.html