Online Upper Case Converter

Write a Java program that reads a text file and writes the content into a new file. During the read-write process, convert all the upper case letters into lower case ones. In other words, your programming task is to create a new file with the same content of the original file, only that all the upper case letters are converted into lower case ones in the new file

When I run this code, no matter the file name it is showing it does not exist. I have created a file named input.txt and it is supposed to convert the data into all lowercase letters.

import java.io.*;import java.util.Scanner;public class UpperCaseFileConverter{    public static void main(String[] args) throws IOException    {    Scanner scanner = new Scanner(System.in);    String userFileName;    System.out.println( "Please enter file name. Please enter \"input.txt\" ");    userFileName = scanner.nextLine();    File file = new File(userFileName);    while(!file.exists() )    {        System.out.println( userFileName + " does not exist. Please try again.Please enter \"input.txt\" ");        userFileName = scanner.nextLine();        file = new File(userFileName);    }    Scanner fileToScan = new Scanner(file);    PrintWriter fileToWrite = new PrintWriter ("OUTPUT.TXT");    while(fileToScan.hasNext() )    {        fileToWrite.println( fileToScan.nextLine().toLowerCase() );    }    fileToWrite.close();    fileToScan.close();    }}

The output should create a new file but it just keeps saying the files do not exist.

Let's say I have a function that takes a string input.

the string input looks like this: "first_time_run"

Below is my code

function changeInput (str) {  // your code here  return str[0].toUpperCase()+id.slice(1)}

The code above returns First_time_run when I want it to return First_Time_Run

What am I doing wrong?

I have a mixed dataframe of character and numeric variables.

city,hs_cd,sl_no,col_01,col_02,col_03Austin,1,2,,46,FemaleAustin,1,3,,32,MaleAustin,1,4,,27,MaleAustin,1,5,,20,FemaleAustin,2,2,,42,FemaleAustin,2,1,,52,MaleAustin,2,3,,25,MaleAustin,2,4,,22,FemaleAustin,3,3,,30,FemaleAustin,3,1,,65,Female

I want to convert all the lower-case characters in the dataframe to uppercase. Is there any way to do this in one shot without doing it repeatedly over each character-variable?

I'm using notepad++ and I'm finding that when I use regex to search for strings where I specifically want to find lowercase letters ("[a-z]") it will sometimes return uppercase letters.

I originally was searching using the string:

^[A-Z][a-z].+?$

With the purpose of deleting any line in my file that began with an uppercase character, followed by a lowercase, followed by anything until the end of the line. However, this returned lines like, "CLONE" and "DISEASE" which were only capital letters. Out of curiosity, I tried:

^[a-z].+?$

And it still returned those lines in all-caps. Finally, I tried:

^[\u0061-\u007A].+?$

And it still returned lines of all-caps text. Is there something outside of my brackets that's causing this to happen?

i'm trying to write a regex to match the Canadian Postcode format from a list.

However, the below regex matches also strings that contain lowercases. I just want to match postcodes that contain only uppercase and if they contain a lowercase, it should not match.

Any help?

This is the regex:

[A-Z][0-9]