Online Lower 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.

I am trying to create a gui helps me to update existing xlsm file easier in a simple gui.

So I need now to create a UI Element Searchbox with filters some thing like this

so how to update this xlsm file by create a gui like this with a simple list view contains check boxes contains master primary key values in column in existing xlsm file, as I think pandas and openpyxl could help me to create an array and put this column values in this check box list, and this is the excel file I want to updatem and this column I marked I want want to put this values in this list check box

.

So If there's any way to create some thing like this or tutorial for this?

I Tried to create something like this but without check boxe.

and this is my code

from tkinter import *import pandas as pdimport os# First create application classclass Application(Frame):    def __init__(self, master=None):        Frame.__init__(self, master)        self.pack()        self.create_widgets()    # Create main GUI window    def create_widgets(self):        self.search_var = StringVar()        self.search_var.trace("w", lambda name, index, mode: self.update_list())        self.entry = Entry(self, textvariable=self.search_var, width=13)        self.lbox = Listbox(self, width=45, height=15)        self.entry.grid(row=0, column=0, padx=10, pady=3)        self.lbox.grid(row=1, column=0, padx=10, pady=3)        # Function for updating the list/doing the search.        # It needs to be called here to populate the listbox.        self.update_list()    def update_list(self):        search_term = self.search_var.get()        # Just a generic list to populate the listbox        mydir = (os.getcwd()).replace('\\', '/') + '/'        mySiteCode = pd.read_excel(r'' + mydir + 'Governance_Tracker - Copy - Copy.xlsm', usecols=['SiteCode'],                                        encoding='latin-1', header=1)        a = mySiteCode['SiteCode'].values.tolist()        self.lbox.delete(0, END)        for item in a:            if search_term.lower() in item.lower():                self.lbox.insert(END, item)root = Tk()root.title('Filter Listbox Test')app = Application(master=root)print'Starting mainloop()'app.mainloop()

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 have a large number of data frame objects, and I want to apply a function that only converts the character strings to lowercase and leaves the classes of every thing else alone.

I have tried mutate_all(df,tolower) but that affected all variables/columns

I have tried mutate_at(names(select_if(df,is.character)),tolower) and this does work on an individual dataframe. But I need to do this across many data frames all at the same time. I am really bad at Iteration and loops, so if code that iterates this line of code over every object may be a solution.

Or, because I also have these dataframes in a list, I have tried

modify_depth(df,.depth = 2, mutate_at(names(select_if(,is.character)),tolower))But that did not work. modify is in the purrr package

library(dplyr)library(purrr)data_frame_Rate_Table <- data.frame(Policy_Class = c("rED", "WhIte","BlUe"),                                   Rate=c(3,9,19),"Factor_1"= 1:3, Factor_2=7:9, stringsAsFactors = FALSE)data_frame_Policyholders <- data.frame(Policy_number  = 1:10,                                       Policy_Class=rep(c("REd","red","wHite","BLue","bluE"),2),                                       Risk=c(rep("HiGh",5),rep("LOW",5)),                                        Lapse=rep(c("Y","N"),5), stringsAsFactors = FALSE)data_frame_list <- list(data_frame_Policyholders, data_frame_Rate_Table)

I would just like all character strings to be lowercase without affecting the other classes.

Reading the PostgreSQL docs, I see both upper and lower case used for SQL keywords, types and functions, for example. I'm wondering if there is a common practice that most folks follow.

Basically, I want to find a convention to follow and stick to it. e.g. the ANSI SQL Docs seem to always use uppercase for keywords like SELECT, AS, types like NUMERIC and function calls like CAST().

Is there a recommended or at least prevailing convention?