Programming Articles - Page 929 of 3366

The dnsPromises.resolveTxt() method uses the DNS protocol to resolve the text search (TXT records) for the hostname. The promise is resolved with a twodimensional array of the text records available for the hostname on success.SyntaxdnsPromises.resolveTxt(hostname)ParametersIt takes only one parameterhostname – This parameter takes input for the hostname to be resolved.Example 1Create a file with the name "resolveTxt.js" and copy the following code snippet. After creating the file, use the command "node resolveTxt.js" to run this code.// dns.resolveTxt() Demo Example // Importing the dns module const dns = require('dns'); const dnsPromises = dns.promises; // Passing IP to find the ... Read More

The dnsPromises.lookup() method resolves the hostname (e.g., tutorialspoint.com) into the first found A IPv4) or AAAA (IPv6) record. The properties available under the options are optional.dns.lookup() does not have anything to do with the DNS protocol. The implementation uses an OS facility that can associate names with addresses and vice versa.The difference between the dnsPromises and dns module is that dns.promises provides an alternative way to asynchronous DNS methods that return Promise objects instead of callbacks.SyntaxdnsPromises.lookup(hostname, [options])Parametershostname – This is the website hostname for which you want to look up the DNS values.options – It can have the following optionsfamily ... Read More

The process.emitWarning() method can be used to emit custom or user-defined process warnings. This can be listened by adding a handler to the warning event.Syntaxprocess.emitWarning(warning, [options])Parameterswarning – This is the warning that will be emitted.options –type – This is the type of warning being emitted. Default ‘Warning’code – This is a unique identifier for the warning that will be emitted.ctor – This is an optional function used to limit the generated stack trace.detail – This is the additional text to be included with the error.Example 1Create a file with the name "warning.js" and copy the following code snippet. After creating ... Read More

The dns.resolveTxt() method uses the DNS protocol to resolve the text queries (TXT Records) for the hostname. The addresses argument passed to the callback function is a two-dimensional array that contains the array of text records available for the hostname.Syntaxdns.resolveTxt(hostname, callback)Parametershostname – This parameter takes input for hostname to be resolvedcallback – This function will catch errors, if any.records – Returns TXT records for the hostname.Example 1Create a file with the name "resolveTxt.js" and copy the below code snippet. After creating file use the command "node resolveTxt.js" to run this code.// dns.resolveTxt() Demo Example // Importing the dns module ... Read More

process.report is an object whose methods generate the diagnostic reports for the current process. It is found under the process module.Syntaxprocess.reportExample 1Create a file with the name "report.js" and copy the following code snippet. After creating the file, use the command "node report.js" to run this code.// process.report Demo Example // Importing the process module const process = require('process'); // Getting reports for the below processes const reports = process.report; // Printing out the result console.log(reports)OutputuC:\homeode>> node report.js {    writeReport: [Function: writeReport],    getReport: [Function: getReport],    directory: [Getter/Setter],    filename: [Getter/Setter],    compact: [Getter/Setter],   ... Read More

The dns.lookup() method resolves the host name (e.g., tutorialspoint.com) into the first found A IPv4) or AAAA (IPv6) record. The properties available under the options are optional. dns.lookup() does not have anything to do with the DNS protocol. The implementation uses an OS facility that can associate names with addresses and vice versa.Syntaxdns.lookup(hostname, [options], callback)ParametersThe above parameters are defined as below −hostname – This is the website hostname for which you want to look up the DNS values.options – It can have the following optionsfamily – It can have the values 4, 6, or 0 only. The value "0" indicates ... Read More

The dns.resolveNs() method uses the DNS protocol to resolve the nameserver records (NS Records) for the hostname. The addresses argument passed to the callback function will contain an array of nameserver records for the hostname.Syntaxdns.resolveNs(hostname, callback)ParametersThe above parameters are defined as below −hostname – This parameter takes input for the hostname to be resolved.callback – This function will catch errors, if any.records – Returns the nameserver (NS) records for the hostname.Example 1Create a file "resolveNs.js" and copy the following code snippet. After creating the file, use the command "node resolveNs.js" to run this code:// dns.resolveNs() Demo Example // Importing ... Read More

To create a data.table object of combination of correlation coefficients, we first need to find the correlation matrix then the combination of variables for which the correlation matrix is created then data.table will be used to combine the combination of variables and the correlation coefficients.Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −x1

To create a graph without background panel, we can use theme function of ggplot2 package where we can set panel.background argument to blank.For Example, if we have a data frame called df that contains two columns say x and y then we can create scatterplot between x and y without background panel using ggplot2 by using the below command −ggplot(df,aes(x,y))+geom_point()+theme(panel.background=element_blank())ExampleConsider the below data frame −x

To create a graph using ggplot2 without axes ticks and axes labels, we can use theme function where we can use set axes ticks and axis labels to blank with the help of arguments corresponding to each axes such as axis.ticks.x, axis.ticks.y, axis.text.x, and axis.text.y.To understand how it works, check out the below Example.ExampleConsider the below data frame −x