Pandas 数据框：没有要绘制的数字数据

Question

I have a table stored in a database in MySQL .

I fetched the results using MySQL connector and copied it to DataFrame. There are no problems till that.

Now as I'm taking the results from MySQL, they are in the form of strings, so I've converted the strings to int for the values of CONFIRMED_CASES , and leave the STATE_NAME as str . Now I want to plot it in a bar graph, with Numeric data as CONFIRMED_CASES and state names as STATE_NAME but it shows me this error:

Traceback (most recent call last):
  File "c:\Users\intel\Desktop\Covid Tracker\get_sql_data.py", line 66, in <module>
    fd.get_graph()
  File "c:\Users\intel\Desktop\Covid Tracker\get_sql_data.py", line 59, in get_graph
    ax = df.plot(y='STATE_NAME', x='CONFIRMED_CASES',
    ...
    raise TypeError("no numeric data to plot")
TypeError: no numeric data to plot

Here's my code:

from operator import index
from sqlalchemy import create_engine
import mysql.connector
import pandas as pd
import matplotlib.pyplot as plt

mydb = mysql.connector.connect(
    host="localhost",
    user="abhay",
    password="1234",
    database="covid_db"
)

mycursor = mydb.cursor()


class fetch_data():
    def __init__(self):
        ...

    def get_data(self, cmd):
        ...

    def get_graph(self):
        mydb = mysql.connector.connect(
            host="localhost",
            user="abhay",
            password="1234",
            database="covid_db"
        )

        mycursor = mydb.cursor(buffered=True)

        mycursor.execute(
            "select CONFIRMED_CASES from india;")
        query = mycursor.fetchall()

        # the data was like 10,000 so I removed the ',' and converted it to int
        query = [int(x[0].replace(',', '')) for x in query]
        print(query)

        query2 = mycursor.execute(
            "select STATE_NAME from india;")
        query2 = mycursor.fetchall()

        # this is the query for state name and i kept it as str only...
        query2 = [x[0] for x in query2]
        print(query2)

        df = pd.DataFrame({
            'CONFIRMED_CASES': [query],
            'STATE_NAME': [query2],
        })

        # it gives me the error here...
        ax = df.plot(y='STATE_NAME', x='CONFIRMED_CASES',
                kind='bar')

        ax.ticklabel_format(style='plain', axis='y')
        plt.show()


fd = fetch_data()
fd.get_graph()

I don't know why there is no numeric value. I set it to int , but still...

Answer 1

在绘制图形之前使用以下代码将数据转换为整数。

df['CONFIRMED_CASES'] = df['CONFIRMED_CASES'].astype('int64')

Answer 2

Your dataframe is defined using lists of a list. query and query2 are lists already. Define your dataframe as:

df = pd.DataFrame({
            'CONFIRMED_CASES': query, # no brackets
            'STATE_NAME': query2,     # no brackets
        })

Answer 3

Heyy guys, It's solved. I used query.values and it worked...