Programming Articles - Page 1044 of 3363

The app.post() method routes all the HTTP POST requests to the specified path with the specified callback functions.Syntaxapp.path(path, callback, [callback])Parameterspath − This is the path for which the middleware function is invoked. A path can be a string, path pattern, a regular expression or an array of all these.callback − These are the middleware functions or a series of middleware functions that acts like a middleware except that these callbacks can invoke next (route).Example 1Create a file with the name "appPost.js" and copy the following code snippet. After creating the file, use the command "node appPost.js" to run this code.// ... Read More

The app.path() method returns the canonical path. The path is returned as a string. It is better to use the req.baseUrl method since the app.path() method can be very complicated in complex cases of mounted apps.Syntaxapp.path( )Example 1Create a file with the name "appPath.js" and copy the following code snippet. After creating the file, use the command "node appPath.js" to run this code.// app.path() Demo Example // Importing the express module var express = require('express'); // Initializing the express and port number var app = express(); var PORT = 3000; // Assigning express constructor var app = ... Read More

The app.param() method is basically used for adding the callback triggers to the route parameters, where name represents the name of the parameter or an array of them and callback represents the callback function.Syntaxapp.param([name], callback)Parametersname − Represents the name of the parameter or array of parameters as required.callback − Represents the callback function. The parameters of the callback function include the request object, the response object, the next middleware, the value of the parameter, and the name of the parameter in the same order.ExampleCreate a file with the name "appParam.js" and copy the following code snippet. After creating the file, ... Read More

The app.mountpath property contains those path patterns on which a sub-app was mounted. A sub-app can be defined as an instance of Express that may be used for handling the request to a route.This property is similar to the baseUrl property of the req object; the only difference is that req.baseUrl returns the matched URL path instead of the matched patterns.Syntaxapp.mountpathExample 1Create a file "appMountpath.js" and copy the following code snippet. After creating the file, use the command "node appMountpath" to run this code.// app.mountpath code Demo Example // Importing the express module var express = require('express'); // ... Read More

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

Point Plot in Seaborn is used to show point estimates and confidence intervals using scatter plot glyphs. The seaborn.pointplot() is used for this. Display Standard Deviation of Observations using confidence interval ci parameter value "sd" in 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”. Display Standard Deviation of Observations using confidence interval parameter value "sd"sb.pointplot( ... Read More

Box Plot in Seaborn is used to draw a box plot to show distributions with respect to categories. The seaborn.boxplot() is used for this. Use the "orient” parameter for orientation of each numeric variable.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 box plot using the orient parameter for orientation of each numeric variable −sb.boxplot( data = dataFrame, orient="h")ExampleFollowing is the code −import seaborn ... 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