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Python Articles
Page 749 of 855
Making matplotlib scatter plots from dataframes in Python's pandas
Using Pandas, we can create a dataframe and can create a figure and axes variable using subplot() method. After that, we can use the ax.scatter() method to get the required plot.StepsMake a list of the number of students.Make a list of marks that have been obtained by the students.To represent the color of each scattered point, we can have a list of colors.Using Pandas, we can have a list representing the axes of the data frame.Create fig and ax variables using subplots method, where default nrows and ncols are 1.Set the “Students count” label using plt.xlabel() method.Set the “Obtained marks” ...
Read MoreManually add legend Items Python Matplotlib
Using plt.legend() method, we can create a legend, and passing frameon would help to keep the border over there.StepsSet the X-axis label using plt.xlabel() method.Set the Y-axis label using plt.ylabel() method.Draw lines using plot() method.Location and legend drawn flags can help to find a location and make the flag True for the border.Set the legend with “blue” and “orange” elements.To show the figure use plt.show() method.Exampleimport matplotlib.pyplot as plt plt.ylabel("Y-axis ") plt.xlabel("X-axis ") plt.plot([9, 5], [2, 5], [4, 7, 8]) location = 0 # For the best location legend_drawn_flag = True plt.legend(["blue", "orange"], loc=0, frameon=legend_drawn_flag) plt.show()Output
Read MoreShow only certain items in legend Python Matplotlib
Using plt.legend(), we can add or show certain items just by putting the values in the list.StepsSet the X-axis label using plt.xlabel() method.Set the Y-axis label using plt.ylabel() method.Plot the lines using the lists that are passed in the plot() method argument.Location and legend_drawn flags can help to find a location and make the flag True for border.Set the legend with “blue” and “orange” elements.To show the figure use plt.show() method.Exampleimport matplotlib.pyplot as plt plt.ylabel("Y-axis ") plt.xlabel("X-axis ") plt.plot([9, 5], [2, 5], [4, 7, 8]) location = 0 # For the best location legend_drawn_flag = True plt.legend(["blue", ...
Read MoreBlurring an image using the OpenCV function blur()
In this program, we will blur an image using the opencv function blur().AlgorithmStep 1: Import OpenCV. Step 2: Import the image. Step 3: Set the kernel size. Step 4: Call the blur() function and pass the image and kernel size as parameters. Step 5: Display the results.Original ImageExample Codeimport cv2 image = cv2.imread("testimage.jpg") kernel_size = (7,7) image = cv2.blur(image, kernel_size) cv2.imshow("blur", image)OutputBlurred ImageExplanationThe kernel size is used to blur only a small part of an image. The kernel moves across the entire image and blurs the pixels it covers.
Read MoreHow to create a simple screen using Tkinter?
We will create a simple screen using the Tkinter library.AlgorithmStep 1: Import tkinter. Step 2: Create an object of the tkinter class. Step 3: Display the screen.Example Codeimport tkinter as tk window = tk.Tk()Output
Read MorePandas program to convert a string of date into time
In this program, we will convert a date string like "24 August 2020" to 2020-08-24 00:00:00. We will use the to_datetime() function in pandas library to solve this task.AlgorithmStep 1: Define a Pandas series containing date string. Step 2: Convert these date strings into date time format using the to_datetime format(). Step 3: Print the results.Example Codeimport pandas as pd series = pd.Series(["24 August 2020", "25 December 2020 20:05"]) print("Series: ", series) datetime = pd.to_datetime(series) print("DateTime Format: ", datetime)OutputSeries: 0 24 August 2020 1 25 December 2020 20:05 dtype: object DateTime Format: 0 2020-08-24 00:00:00 1 2020-12-25 20:05:00 dtype: datetime64[ns]
Read MoreHow to use regular expressions (Regex) to filter valid emails in a Pandas series?
A regular expression is a sequence of characters that define a search pattern. In this program, we will use these regular expressions to filter valid and invalid emails.We will define a Pandas series with different emails and check which email is valid. We will also use a python library called re which is used for regex purposes.AlgorithmStep 1: Define a Pandas series of different email ids. Step 2: Define a regex for checking validity of emails. Step 3: Use the re.search() function in the re library for checking the validity of the email.Example Codeimport pandas as pd import re ...
Read MoreHow to get the nth percentile of a Pandas series?
A percentile is a term used in statistics to express how a score compares to other scores in the same set. In this program, we have to find nth percentile of a Pandas series.AlgorithmStep 1: Define a Pandas series. Step 2: Input percentile value. Step 3: Calculate the percentile. Step 4: Print the percentile.Example Codeimport pandas as pd series = pd.Series([10, 20, 30, 40, 50]) print("Series:", series) n = int(input("Enter the percentile you want to calculate: ")) n = n/100 percentile = series.quantile(n) print("The {} percentile of the given series is: {}".format(n*100, percentile))OutputSeries: 0 10 1 ...
Read MoreHow to calculate the frequency of each item in a Pandas series?
In this program, we will calculate the frequency of each element in a Pandas series. The function value_counts() in the pandas library helps us to find the frequency of elements.AlgorithmStep 1: Define a Pandas series. Step 2: Print the frequency of each item using the value_counts() function.Example Codeimport pandas as pd series = pd.Series([10,10,20,30,40,30,50,10,60,50,50]) print("Series:", series) frequency = series.value_counts() print("Frequency of elements:", frequency)OutputSeries: 0 10 1 10 2 20 3 30 4 40 5 30 6 50 7 10 8 60 9 50 10 50 dtype: int64 Frequency of elements: 50 3 10 3 30 2 20 1 40 1 60 1 dtype: int64
Read MoreFinding the multiples of a number in a given list using NumPy
In this program, we will find the index position at which a multiple of a given number exists. We will use both the Numpy and the Pandas library for this task.AlgorithmStep 1: Define a Pandas series. Step 2: Input a number n from the user. Step 3: Find the multiples of that number from the series using argwhere() function in the numpy library.Example Codeimport numpy as np listnum = np.arange(1, 20) multiples = [] print("NumList:", listnum) n = int(input("Enter the number you want to find multiples of: ")) for num in listnum: if num % n == ...
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