In this article, we see how to make a Command Line application todo list in python. Todo list is a basic application in which users can add items. It’s a list of tasks you need to complete or things that you want to do. In to-do, list tasks are organized in order of priority. One of the most important reasons you should use a to-do list is that it will help you stay organized.
In this article we make a to-do list using the command line. By Using a to-do list as a command-line application we can organize our to-do list through a command prompt, and we do not need to run any script or program explicitly.
Basic Functions of todo list are:
- Add a new todo
- Delete a todo
- Complete a todo
- Show remaining todos
- Show statistics of todo
Example
Note: In Windows Command Prompt to run the application → type todo or.\todo
In shell or git bash --> type ./todo
- To create todo list application we have to follow these steps:
- Create a folder named todolist
- Create a file todo.py in the created folder
- If you are a window user then Create another file todo.bat file. This is a batch file. And it is used to run the python script
- If you are Linux user then create a file named as todo.sh. This is used to run the python script.
todo.bat:
@echo off python3 todo.py %1 %2
todo.sh:
python todo.py "$@"
Create a symbolic link to the executable file:
In Windows (In command prompt or Powershell)
To create a symbolic link on Windows, you’ll need to run either the Windows Command Prompt or Windows Powershell **with administrator privileges**. To do so, right-click on the icon for Command Prompt, or Powershell, and choose the _”Run as Administrator”_ option.
mklink todo todo.bat
In Linux or in the shell(as git bash)
$ ln -s todo.sh todo
Now we have to code the functions of our to-do list.
So we write the code in todo.py
Python3
# module requiredimport sysimport datetime |
Help function: The help function is used to provide the way how a user can use the todo list. And Help function is like the documentation of todo application.
Python3
# help functiondef help(): sa = """Usage :-$ ./todo add "todo item" # Add a new todo$ ./todo ls # Show remaining todos$ ./todo del NUMBER # Delete a todo$ ./todo done NUMBER # Complete a todo$ ./todo help # Show usage$ ./todo report # Statistics""" sys.stdout.buffer.write(sa.encode('utf8')) |
Function to add items in todo list: Add function is used to add new items to todo list
Python3
# function to add item in todo listdef add(s): f = open('todo.txt', 'a') f.write(s) f.write("\n") f.close() s = '"'+s+'"' print(f"Added todo: {s}") |
The function to print the todo list function is used to print the items that are present in our todo list. Todo items are printed in ascending order.
Python3
# Function to print the todo list itemsdef ls(): try: nec() l = len(d) k = l for i in d: sys.stdout.buffer.write(f"[{l}] {d[l]}".encode('utf8')) sys.stdout.buffer.write("\n".encode('utf8')) l = l-1 except Exception as e: raise e |
Function to Complete a todo: Function defines the completed task and this completed task is added in done.txt.
Python3
# Function to Complete a tododef done(no): try: nec() no = int(no) f = open('done.txt', 'a') st = 'x '+str(datetime.datetime.today()).split()[0]+' '+d[no] f.write(st) f.write("\n") f.close() print(f"Marked todo #{no} as done.") with open("todo.txt", "r+") as f: lines = f.readlines() f.seek(0) for i in lines: if i.strip('\n') != d[no]: f.write(i) f.truncate() except: print(f"Error: todo #{no} does not exist.") |
Function to show the statistics of todolist: The “report” function is used to show the complete statistics. It prints total no of the completed task and total no of the pending task.
Python3
# Function to show report/statistics of todo listdef report(): nec() try: nf = open('done.txt', 'r') c = 1 for line in nf: line = line.strip('\n') don.update({c: line}) c = c+1 print( f'{str(datetime.datetime.today()).split()[0]} Pending : {len(d)} Completed : {len(don)}') except: print( f'{str(datetime.datetime.today()).split()[0]} Pending : {len(d)} Completed : {len(don)}') |
Function to delete an item from todo list: deL function is used to delete an item from todo list. It deletes todo item based on the item number
Python3
# codedef deL(no): try: no = int(no) nec() # utility function defined in main with open("todo.txt", "r+") as f: lines = f.readlines() f.seek(0) for i in lines: if i.strip('\n') != d[no]: f.write(i) f.truncate() print(f"Deleted todo #{no}") except Exception as e: print(f"Error: todo #{no} does not exist. Nothing deleted.") |
Main function and utility function
Python3
# codedef nec(): # utility function used in done and report function try: f = open('todo.txt', 'r') c = 1 for line in f: line = line.strip('\n') d.update({c: line}) c = c+1 except: sys.stdout.buffer.write("There are no pending todos!".encode('utf8'))# Main programif __name__ == '__main__': try: d = {} don = {} args = sys.argv if(args[1] == 'del'): args[1] = 'deL' if(args[1] == 'add' and len(args[2:]) == 0): sys.stdout.buffer.write( "Error: Missing todo string. Nothing added!".encode('utf8')) elif(args[1] == 'done' and len(args[2:]) == 0): sys.stdout.buffer.write( "Error: Missing NUMBER for marking todo as done.".encode('utf8')) elif(args[1] == 'deL' and len(args[2:]) == 0): sys.stdout.buffer.write( "Error: Missing NUMBER for deleting todo.".encode('utf8')) else: globals()[args[1]](*args[2:]) except Exception as e: s = """Usage :-$ ./todo add "todo item" # Add a new todo$ ./todo ls # Show remaining todos$ ./todo del NUMBER # Delete a todo$ ./todo done NUMBER # Complete a todo$ ./todo help # Show usage$ ./todo report # Statistics""" sys.stdout.buffer.write(s.encode('utf8')) |
Below is the implementation:
Python3
# Complete codeimport sysimport datetimedef help(): sa = """Usage :-$ ./todo add "todo item" # Add a new todo$ ./todo ls # Show remaining todos$ ./todo del NUMBER # Delete a todo$ ./todo done NUMBER # Complete a todo$ ./todo help # Show usage$ ./todo report # Statistics""" sys.stdout.buffer.write(sa.encode('utf8'))def add(s): f = open('todo.txt', 'a') f.write(s) f.write("\n") f.close() s = '"'+s+'"' print(f"Added todo: {s}")def ls(): try: nec() l = len(d) k = l for i in d: sys.stdout.buffer.write(f"[{l}] {d[l]}".encode('utf8')) sys.stdout.buffer.write("\n".encode('utf8')) l = l-1 except Exception as e: raise edef deL(no): try: no = int(no) nec() with open("todo.txt", "r+") as f: lines = f.readlines() f.seek(0) for i in lines: if i.strip('\n') != d[no]: f.write(i) f.truncate() print(f"Deleted todo #{no}") except Exception as e: print(f"Error: todo #{no} does not exist. Nothing deleted.")def done(no): try: nec() no = int(no) f = open('done.txt', 'a') st = 'x '+str(datetime.datetime.today()).split()[0]+' '+d[no] f.write(st) f.write("\n") f.close() print(f"Marked todo #{no} as done.") with open("todo.txt", "r+") as f: lines = f.readlines() f.seek(0) for i in lines: if i.strip('\n') != d[no]: f.write(i) f.truncate() except: print(f"Error: todo #{no} does not exist.")def report(): nec() try: nf = open('done.txt', 'r') c = 1 for line in nf: line = line.strip('\n') don.update({c: line}) c = c+1 print( f'{str(datetime.datetime.today()).split()[0]} Pending : {len(d)} Completed : {len(don)}') except: print( f'{str(datetime.datetime.today()).split()[0]} Pending : {len(d)} Completed : {len(don)}')def nec(): try: f = open('todo.txt', 'r') c = 1 for line in f: line = line.strip('\n') d.update({c: line}) c = c+1 except: sys.stdout.buffer.write("There are no pending todos!".encode('utf8'))if __name__ == '__main__': try: d = {} don = {} args = sys.argv if(args[1] == 'del'): args[1] = 'deL' if(args[1] == 'add' and len(args[2:]) == 0): sys.stdout.buffer.write( "Error: Missing todo string. Nothing added!".encode('utf8')) elif(args[1] == 'done' and len(args[2:]) == 0): sys.stdout.buffer.write( "Error: Missing NUMBER for marking todo as done.".encode('utf8')) elif(args[1] == 'deL' and len(args[2:]) == 0): sys.stdout.buffer.write( "Error: Missing NUMBER for deleting todo.".encode('utf8')) else: globals()[args[1]](*args[2:]) except Exception as e: s = """Usage :-$ ./todo add "todo item" # Add a new todo$ ./todo ls # Show remaining todos$ ./todo del NUMBER # Delete a todo$ ./todo done NUMBER # Complete a todo$ ./todo help # Show usage$ ./todo report # Statistics""" sys.stdout.buffer.write(s.encode('utf8')) |
Output:
