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The app.locals object defines the properties that are local variables inside an application. Once the value of app.locals property is set, it persists throughout the life of the application. The res.locals property is valid only for the lifetime of the request.Syntaxapp.localsExample 1Create a file "appLocals.js" and copy the following code snippet. After creating the file, use the command "node appLocals.js" to run this code.// app.locals code Demo Example // Importing the express module var express = require('express'); // Initializing the express and port number var app = express(); // Setting the below email throught out the application ... Read More
The app.listen() method binds itself with the specified host and port to bind and listen for any connections. If the port is not defined or 0, an arbitrary unused port will be assigned by the operating system that is mainly used for automated tasks like testing, etc.The app object returned by express() is a JavaScript function, that is passed to Node’s HTTP servers as a callback which handles the requests. This makes the application to provide both HTTP and HTTPS versions of the same app with the same code base, as the app does not inherit from these.Syntaxapp.listen([port], [host], [backlog], ... Read More
We can plot Line Graph, Pie Chart, Histogram, etc. with a Pandas DataFrame using Matplotlib. For this, we need to import Pandas and Matplotlib libraries −import pandas as pd import matplotlib.pyplot as pltLet us begin plotting −Line GraphExampleFollowing is the code −import pandas as pd import matplotlib.pyplot as plt # creating a DataFrame with 2 columns dataFrame = pd.DataFrame( { "Car": ['BMW', 'Lexus', 'Audi', 'Mustang', 'Bentley', 'Jaguar'], "Reg_Price": [2000, 2500, 2800, 3000, 3200, 3500], "Units": [100, 120, 150, 170, 180, 200] ... Read More
We will group Pandas DataFrame using the groupby(). Select the column to be used using the grouper function. We will group year-wise and calculate sum of Registration Price with year interval for our example shown below for Car Sale Records.At first, let’s say the following is our Pandas DataFrame with three columns −# dataframe with one of the columns as Date_of_Purchase dataFrame = pd.DataFrame( { "Car": ["Audi", "Lexus", "Tesla", "Mercedes", "BMW", "Toyota", "Nissan", "Bentley", "Mustang"], "Date_of_Purchase": [pd.Timestamp("2021-06-10"), pd.Timestamp("2019-07-11"), pd.Timestamp("2016-06-25"), pd.Timestamp("2021-06-29"), ... Read More
To select a subset of rows and columns, use the loc. Use the index operator i.e. the square bracket and set conditions in the loc.Let’s say the following are the contents of our CSV file opened in Microsoft Excel −At first, load data from a CSV file into a Pandas DataFrame −dataFrame = pd.read_csv("C:\Users\amit_\Desktop\SalesData.csv")Select a subset of rows and columns combined. Right column displays the column you want to display i.e. Cars column here −dataFrame.loc[dataFrame["Units"] > 100, "Car"]ExampleFollowing is the code −import pandas as pd # Load data from a CSV file into a Pandas DataFrame: dataFrame = pd.read_csv("C:\Users\amit_\Desktop\SalesData.csv") ... Read More
Point Plot in Seaborn is used to show point estimates and confidence intervals using scatter plot glyphs. The seaborn.pointplot() is used for this. For explicit order, use the order parameter of the pointplot() method.Let’s say the following is our dataset in the form of a CSV file − Cricketers.csvAt first, import the required libraries −import seaborn as sb import pandas as pd import matplotlib.pyplot as pltLoad data from a CSV file into a Pandas DataFrame −dataFrame = pd.read_csv("C:\Users\amit_\Desktop\Cricketers.csv")Plotting point plot with “Academy” and “Age”. Control order by passing an explicit order i.e. ordering on the basis of "Academy". Ordering using ... Read More
The app.engine() method is used for registering the given template engine callback as "ext". The require() method needs the engine based on the function by default.Use the following methods for engines that do not provide the extensions (or want to map different extensions) or express out of the box.app.engine('html', require('ejs').renderFile)Syntaxapp.engine(ext, callback)Example 1Create a file with the name "appEngine.js" and copy the following code snippet. After creating the file, use the command "node appEngine.js" to run this code.// app.engine() Method Demo Example // Importing the express module const express = require('express'); // Initializing the express and port number var ... Read More
To create a Time Series Plot with multiple columns using Line Plot, use the lineplot(). At first, import the required libraries −import seaborn as sb import pandas as pd import matplotlib.pyplot as pltCreate a DataFrame. We have multiple columns in our DataFrame −dataFrame = pd.DataFrame({'Date_of_Purchase': ['2018-07-25', '2018-10-25', '2019-01-25', '2019-05-25', '2019-08-25', '2020-09-25', '2021-03-25'], 'Units Sold': [98, 77, 51, 70, 70, 87, 76], 'Units Returned' : [60, 50, 40, 57, 62, 51, 60] })Plot time series plot for multiple columns −sb.lineplot(x="Date_of_Purchase", y="Units Sold", data=dataFrame) sb.lineplot(x="Date_of_Purchase", y="Units Returned", data=dataFrame)ExampleFollowing is the code −import seaborn as sb import pandas as pd import matplotlib.pyplot as ... Read More
Horizontal point plots are a plotting based on the values of x and y i.e. the columns of the dataset you consider. Point Plot in Seaborn is used to show point estimates and confidence intervals using scatter plot glyphs. The seaborn.pointplot() is used for this.Let’s say the following is our dataset in the form of a CSV file − Cricketers.csvAt first, import the required libraries −import seaborn as sb import pandas as pd import matplotlib.pyplot as pltLoad data from a CSV file into a Pandas DataFrame −dataFrame = pd.read_csv("C:\Users\amit_\Desktop\Cricketers.csv")Now, use the pointplot() and set the x and y values −sb.pointplot(x ... Read More
The app.enable() function sets the Boolean setting ‘name’ to ‘true’, where name defines one of the properties from the app settings table. Using the app.set('foo', true) for a Boolean property is same as calling the app.enable('foo') function.Syntaxapp.enable(name)Example 1Create a file with the name "appEnable.js" and copy the following code snippet. After creating the file, use the command "node appEnable.js" to run this code.// app.enable() Method Demo Example // Importing the express module const express = require('express'); // Initializing the express and port number var app = express(); // Initializing the router from express var router = express.Router(); ... Read More