Develop Reference

Opens same registry twice?

I am trying to get all installed programs of my windows computer, therefore I read out the registry.
But somehow python reads the 32bit programs out twice (even though I give him another registry entry)
Here is the code snipped:
def get_programs(registry):
reg = ConnectRegistry(None, HKEY_LOCAL_MACHINE)
programList = []
key = OpenKey(reg, registry)
print(QueryInfoKey(key))
for i in range(0, QueryInfoKey(key)[0]):
programList.append(EnumKey(key, i))
CloseKey(key)
CloseKey(reg)
return programList
I call this function like this:
registry32bit = "SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall"
registry64bit = "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall"
programs32bit = get_programs(registry32bit)
programs64bit = get_programs(registry64bit)
Why does python open and read out the same registry (for 32 bit) twice and return the exactly same list?

This appears to work and uses #eryksun suggestion in a comment below about just letting the redirection happen and not explicitly referencing the Wow6432Node registry key. The central idea is to just specify either the KEY_WOW64_32KEY or KEY_WOW64_64KEY flag when opening the uninstall subkey and let the magic happen.
Note: I also Pythonized the code in the get_programs() function some. This made it shorter and more readable in my opinion.
import sys
from _winreg import *
# Assure registry handle objects with context manager protocol implemented.
if sys.version_info.major*10 + sys.version_info.minor < 26:
raise AssertionError('At least Python 2.6 is required.')
def get_programs(subkey, regBitView):
with ConnectRegistry(None, HKEY_LOCAL_MACHINE) as hive:
with OpenKey(hive, subkey, 0, regBitView | KEY_READ) as key:
return [EnumKey(key, i) for i in range(QueryInfoKey(key)[0])]
UNINSTALL_REG_KEY = r'SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall'
programs32bit = get_programs(UNINSTALL_REG_KEY, KEY_WOW64_32KEY)
programs64bit = get_programs(UNINSTALL_REG_KEY, KEY_WOW64_64KEY)
print('32-bit programs:\n{}'.format(programs32bit))
print('')
print('64-bit programs:\n{}'.format(programs64bit))
Many thanks to #eryksun for the clues and many implementation strategy suggestions.

Python pre-completed/modifieable input [duplicate]

Is it possible for python to accept input like this:
Folder name: Download
But instead of the user typing "Download" it is already there as a initial value. If the user wants to edit it as "Downloads" all he has to do is add a 's' and press enter.
Using normal input command:
folder=input('Folder name: ')
all I can get is a blank prompt:
Folder name:
Is there a simple way to do this that I'm missing?

The standard library functions input() and raw_input() don't have this functionality. If you're using Linux you can use the readline module to define an input function that uses a prefill value and advanced line editing:
import readline
def rlinput(prompt, prefill=''):
readline.set_startup_hook(lambda: readline.insert_text(prefill))
try:
return input(prompt) # or raw_input in Python 2
finally:
readline.set_startup_hook()

I'm assuming you mean from the command-line. I've never seen initial values for command line prompts, they're usually of the form:
Folder [default] :
which in code is simply:
res = raw_input('Folder [default] : ')
res = res or 'default'
Alternatively, you can try to do something using the curses module in Python.

This works in windows.
import win32console
_stdin = win32console.GetStdHandle(win32console.STD_INPUT_HANDLE)
def input_def(prompt, default=''):
keys = []
for c in unicode(default):
evt = win32console.PyINPUT_RECORDType(win32console.KEY_EVENT)
evt.Char = c
evt.RepeatCount = 1
evt.KeyDown = True
keys.append(evt)
_stdin.WriteConsoleInput(keys)
return raw_input(prompt)
if __name__ == '__main__':
name = input_def('Folder name: ')
print
print name

I finally found a simple alternative that works on Windows and Linux. Essentially, i'm using the pyautogui module to simulate the user's input. in practice, it looks like this:
from pyautogui import typewrite
print("enter folder name: ")
typewrite("Default Value")
folder = input()
A Word of Warning:
Theoretically, the user can insert characters in the middle of the "default" input by pressing a key before typewrite finishes.
pyautogui is notoriously unreliable on headless systems, so make sure to provide a backup solution in case the import fails. If you run into No module named 'Xlib', try to install the python3-xlib or python-xlib package (or the xlib module). Running over ssh can also be a problem.
An example fallback implementation:
Since a missing X-server can logically only happen on linux, here's an implementation that uses sth's answer as fallback:
try:
from pyautogui import typewrite
autogui = True
except (ImportError, KeyError):
import readline
autogui = False
def rlinput(prompt, prefill=''):
if autogui:
print(prompt)
typewrite(prefill)
return input()
else:
readline.set_startup_hook(lambda: readline.insert_text(prefill))
try:
return input(prompt)
finally:
readline.set_startup_hook()

I think that the best (the easiest and most portable) solution is a combination of #rlotun and #Stephen answers:
default = '/default/path/'
dir = raw_input('Folder [%s]' % default)
dir = dir or default

I would like to suggest using the clipboard to solve this problem. Paste the clipboard into the input line, edit as required, press enter. Variable clpstack is used to protect existing clipboard contents. This code is for Windows. Linux could use import clipboard.
import pyperclip as clp
clpstack=clp.paste()
clp.copy("192.168.4.1")
HOST = input("Enter telnet host: ")
clp.copy(clpstack)

I found PyInquirer to be very helpful, especially when building interactive console applications frequently. Prompting a user with a default modifiable value would look as follows:
from PyInquirer import prompt
question = [
{
'type': 'input',
'name': 'first_name',
'message': 'Name please',
'default': 'Max'
}
]
answer = prompt(question)
print('Hello {}'.format(answer['first_name']))

Recently faced this problem. None of the above answers seem to be flawless. So I did some research, and found the following solution to be the easiest, and works both for Windows and Linux:
import keyboard
def input_with_default(prompt_, default_):
keyboard.write(default_)
return input(prompt_)
if __name__ == "__main__":
print(input_with_default("Please enter: ", "hello world"))

I like this, It works on window
def inputWdefault(prompt, default):
bck = chr(8) * len(default)
ret = input(prompt + default + bck)
return ret or default

I liked the approach taken by #MCO so I refactored the code. I tested it on X Windows and Microsoft Windows 10 WSL 2 using Microsoft Terminal:
def input_with_default(prompt, prefill=''):
try:
from pyautogui import typewrite
print(prompt)
typewrite(prefill)
return input()
except (ImportError, KeyError):
import readline
readline.set_startup_hook(lambda: readline.insert_text(prefill))
try:
return input(prompt)
finally:
readline.set_startup_hook()

Not the best aproach but for the sake of sharing...
You could use Javascript to get all sort of inputs in IPython Notebook.
from IPython.display import HTML
newvar = ""
htm = """
<input id="inptval" style="width:60%;" type="text" value="This is an editable default value.">
<button onclick="set_value()" style="width:20%;">OK</button>
<script type="text/Javascript">
function set_value(){
var input_value = document.getElementById('inptval').value;
var command = "newvar = '" + input_value + "'";
var kernel = IPython.notebook.kernel;
kernel.execute(command);
}
</script>
"""
HTML(htm)
On the next cell you can use the new variable:
print newvar

We can use Tkinter and use a StringVar to do this. The limitation is that the input is through a Tkinter window.
from tkinter import Tk, LEFT, BOTH, StringVar
from tkinter.ttk import Entry, Frame
class Example(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
self.parent = parent
self.initUI()
def initUI(self):
self.parent.title("Entry")
self.pack(fill=BOTH, expand=1)
self.contents = StringVar()
# give the StringVar a default value
self.contents.set('test')
self.entry = Entry(self)
self.entry.pack(side=LEFT, padx=15)
self.entry["textvariable"] = self.contents
self.entry.bind('<Key-Return>', self.on_changed)
def on_changed(self, event):
print('contents: {}'.format(self.contents.get()))
return True
def main():
root = Tk()
ex = Example(root)
root.geometry("250x100+300+300")
root.mainloop()
if __name__ == '__main__':
main()

If you are writing a CLI, you might want to consider using the python-click library for this.
You would achieve your goal with the following code:
import click
user_input = click.prompt(text="Folder name", default="Download")
print(f"{user_input=}")
If you run this code, and type in nothing, then you get:
$ python3 cli_code.py
Folder name [Download]:
user_input='Download'
If you run this code, and type in 'my-dir', then you get:
$ python3 cli_code.py
Folder name [Download]: my-dir
user_input='my-dir'

Try using an "f-string" and "or" combination, say:
default_name = "that_folder"
this_folder = input(f"Folder name: ({default_name}) ") or default_name
print(this_folder)
If you hit Return without typing in the folder name, the default_name will be assumed.

This is not a very Good Answer but it is a work around for windows. As hard as I tried, I could not get Readline or pyReadline to work on my Windows10 computer with Python Ver 3.5. So I wrote this instead. Not the best code in the world since I've only been using Python for 3 months. But it works.
import os
def note_input(defaultvalue):
#Create a textfile
txtfile = open("txtfile.txt", "w")
#
# populate it with the default value
txtfile.write(defaultvalue)
txtfile.close()
#
# call Notepad
os.system("notepad.exe txtfile.txt")
# input("Just holding until notepad is close : ") (did not need this line)
#
# get the Value Entered/Changed in Notepad
txtfile = open("txtfile.txt", "r")
func_value = txtfile.read()
txtfile.close()
return func_value
# END DEF
Notepad stopped the program from running until it was closed, so the input() line below it was not needed. Once notepad was opened the first time and placed where I wanted it on the screen, It was like a popup input window. I assume you can use any text editor like Notepad++ or Scripe or Code Writer, etc.

If you do that, the user would have to delete the existing word. What about providing a default value if the user hits "return"?
>>> default_folder = "My Documents"
>>> try: folder = input("folder name [%s]:" %default_folder)
... except SyntaxError: folder = default_folder

Python Cmd Tab Completion Problems

I've got an application I'm currently working on for our company. Its currently built around Python's Cmd module, and features tab-completion for a number of tasks.
For some reason however, the Tab completion only currently works on one machine in the building - running the scripts from other machines doesn't allow the tab completion.
Here's the offending code parts:
def populate_jobs_list():
global avail_jobs
avail_jobs = os.walk(rootDir()).next()[1]
print avail_jobs
...
def complete_job(self, text, line, start_index, end_index):
global avail_jobs
populate_jobs_list()
if text:
return [
jobs for jobs in avail_jobs
if jobs.startswith(text)
]
else:
return avail_jobs
def do_job(self, args):
pass
split_args = args.rsplit()
os.environ['JOB'] = args
job_dir = os.path.join( rootDir(), os.getenv('JOB'))
os.environ['JOB_PROPS'] = (job_dir + '\\job_format.opm')
if not os.path.isdir(job_dir):
print 'Job does not exist. Try again.'
return
else:
print('Jobbed into: ' + os.getenv('JOB'))
return
populate_jobs_list()
prompt = outPrompt()
prompt.prompt = '\> '
prompt.cmdloop('Loading...')
Am I missing something obvious here? Just to clarify, on machine A, the tab completion works as intended. When its run on any other machine in the building, it fails to complete.

Check if the environment variable PYTHONSTARTUP is set properly. It should point to a script which in turn needs to do sth like this:
try:
import readline
except ImportError:
sys.stdout.write("No readline module found, no tab completion available.\n")
else:
import rlcompleter
readline.parse_and_bind('tab: complete')
Maybe (some part of) this is only done properly on the one working machine?
Maybe the readline module is available only on the one working machine?

How to check whether screen is off in Mac/Python?

How do I check whether the screen is off due to the Energy Saver settings in System Preferences under Mac/Python?

Quick and dirty solution: call ioreg and parse the output.
import subprocess
import re
POWER_MGMT_RE = re.compile(r'IOPowerManagement.*{(.*)}')
def display_status():
output = subprocess.check_output(
'ioreg -w 0 -c IODisplayWrangler -r IODisplayWrangler'.split())
status = POWER_MGMT_RE.search(output).group(1)
return dict((k[1:-1], v) for (k, v) in (x.split('=') for x in
status.split(',')))
In my computer, the value for CurrentPowerState is 4 when the screen is on and 1 when the screen is off.
Better solution: use ctypes to get that information directly from IOKit.

The only way i can think off is by using OSX pmset Power Management CML Tool
DESCRIPTION
pmset changes and reads power management settings such as idle sleep timing, wake on administrative
access, automatic restart on power loss, etc.
Refer to the following link, it will provide a great deal of information that should aid you in accomplishing exactly what you are looking for.
http://managingamac.blogspot.com/2012/12/power-assertions-in-python.html
I will include the code provided by the link for "saving and documentation" purposes:
#!/usr/bin/python
import ctypes
import CoreFoundation
import objc
import subprocess
import time
def SetUpIOFramework():
# load the IOKit library
framework = ctypes.cdll.LoadLibrary(
'/System/Library/Frameworks/IOKit.framework/IOKit')
# declare parameters as described in IOPMLib.h
framework.IOPMAssertionCreateWithName.argtypes = [
ctypes.c_void_p, # CFStringRef
ctypes.c_uint32, # IOPMAssertionLevel
ctypes.c_void_p, # CFStringRef
ctypes.POINTER(ctypes.c_uint32)] # IOPMAssertionID
framework.IOPMAssertionRelease.argtypes = [
ctypes.c_uint32] # IOPMAssertionID
return framework
def StringToCFString(string):
# we'll need to convert our strings before use
return objc.pyobjc_id(
CoreFoundation.CFStringCreateWithCString(
None, string,
CoreFoundation.kCFStringEncodingASCII).nsstring())
def AssertionCreateWithName(framework, a_type,
a_level, a_reason):
# this method will create an assertion using the IOKit library
# several parameters
a_id = ctypes.c_uint32(0)
a_type = StringToCFString(a_type)
a_reason = StringToCFString(a_reason)
a_error = framework.IOPMAssertionCreateWithName(
a_type, a_level, a_reason, ctypes.byref(a_id))
# we get back a 0 or stderr, along with a unique c_uint
# representing the assertion ID so we can release it later
return a_error, a_id
def AssertionRelease(framework, assertion_id):
# releasing the assertion is easy, and also returns a 0 on
# success, or stderr otherwise
return framework.IOPMAssertionRelease(assertion_id)
def main():
# let's create a no idle assertion for 30 seconds
no_idle = 'NoIdleSleepAssertion'
reason = 'Test of Pythonic power assertions'
# first, we'll need the IOKit framework
framework = SetUpIOFramework()
# next, create the assertion and save the ID!
ret, a_id = AssertionCreateWithName(framework, no_idle, 255, reason)
print '\n\nCreating power assertion: status %s, id %s\n\n' % (ret, a_id)
# subprocess a call to pmset to verify the assertion worked
subprocess.call(['pmset', '-g', 'assertions'])
time.sleep(5)
# finally, release the assertion of the ID we saved earlier
AssertionRelease(framework, a_id)
print '\n\nReleasing power assertion: id %s\n\n' % a_id
# verify the assertion has been removed
subprocess.call(['pmset', '-g', 'assertions'])
if __name__ == '__main__':
main()
https://opensource.apple.com/source/PowerManagement/PowerManagement-211/pmset/pmset.c
The code relies on IOPMLib, which functions to make assertions, schedule power events, measure thermals, and more.
https://developer.apple.com/documentation/iokit/iopmlib_h
To call these functions through Python, we must go through the IOKit Framework.
https://developer.apple.com/library/archive/documentation/DeviceDrivers/Conceptual/IOKitFundamentals/Introduction/Introduction.html
In order for us to manipulate C data types in Python, we'll use a foreign function interface called ctypes.
http://python.net/crew/theller/ctypes/
Here's the wrapper the author describe's on the page; written by Michael Lynn. The code i posted from the Author's link above is a rewrite of this code to make it more understandable.
https://github.com/pudquick/pypmset/blob/master/pypmset.py

Show default value for editing on Python input possible?

Is it possible for python to accept input like this:
Folder name: Download
But instead of the user typing "Download" it is already there as a initial value. If the user wants to edit it as "Downloads" all he has to do is add a 's' and press enter.
Using normal input command:
folder=input('Folder name: ')
all I can get is a blank prompt:
Folder name:
Is there a simple way to do this that I'm missing?

The standard library functions input() and raw_input() don't have this functionality. If you're using Linux you can use the readline module to define an input function that uses a prefill value and advanced line editing:
import readline
def rlinput(prompt, prefill=''):
readline.set_startup_hook(lambda: readline.insert_text(prefill))
try:
return input(prompt) # or raw_input in Python 2
finally:
readline.set_startup_hook()

I'm assuming you mean from the command-line. I've never seen initial values for command line prompts, they're usually of the form:
Folder [default] :
which in code is simply:
res = raw_input('Folder [default] : ')
res = res or 'default'
Alternatively, you can try to do something using the curses module in Python.

This works in windows.
import win32console
_stdin = win32console.GetStdHandle(win32console.STD_INPUT_HANDLE)
def input_def(prompt, default=''):
keys = []
for c in unicode(default):
evt = win32console.PyINPUT_RECORDType(win32console.KEY_EVENT)
evt.Char = c
evt.RepeatCount = 1
evt.KeyDown = True
keys.append(evt)
_stdin.WriteConsoleInput(keys)
return raw_input(prompt)
if __name__ == '__main__':
name = input_def('Folder name: ')
print
print name

I finally found a simple alternative that works on Windows and Linux. Essentially, i'm using the pyautogui module to simulate the user's input. in practice, it looks like this:
from pyautogui import typewrite
print("enter folder name: ")
typewrite("Default Value")
folder = input()
A Word of Warning:
Theoretically, the user can insert characters in the middle of the "default" input by pressing a key before typewrite finishes.
pyautogui is notoriously unreliable on headless systems, so make sure to provide a backup solution in case the import fails. If you run into No module named 'Xlib', try to install the python3-xlib or python-xlib package (or the xlib module). Running over ssh can also be a problem.
An example fallback implementation:
Since a missing X-server can logically only happen on linux, here's an implementation that uses sth's answer as fallback:
try:
from pyautogui import typewrite
autogui = True
except (ImportError, KeyError):
import readline
autogui = False
def rlinput(prompt, prefill=''):
if autogui:
print(prompt)
typewrite(prefill)
return input()
else:
readline.set_startup_hook(lambda: readline.insert_text(prefill))
try:
return input(prompt)
finally:
readline.set_startup_hook()

I think that the best (the easiest and most portable) solution is a combination of #rlotun and #Stephen answers:
default = '/default/path/'
dir = raw_input('Folder [%s]' % default)
dir = dir or default

I would like to suggest using the clipboard to solve this problem. Paste the clipboard into the input line, edit as required, press enter. Variable clpstack is used to protect existing clipboard contents. This code is for Windows. Linux could use import clipboard.
import pyperclip as clp
clpstack=clp.paste()
clp.copy("192.168.4.1")
HOST = input("Enter telnet host: ")
clp.copy(clpstack)

I found PyInquirer to be very helpful, especially when building interactive console applications frequently. Prompting a user with a default modifiable value would look as follows:
from PyInquirer import prompt
question = [
{
'type': 'input',
'name': 'first_name',
'message': 'Name please',
'default': 'Max'
}
]
answer = prompt(question)
print('Hello {}'.format(answer['first_name']))

Recently faced this problem. None of the above answers seem to be flawless. So I did some research, and found the following solution to be the easiest, and works both for Windows and Linux:
import keyboard
def input_with_default(prompt_, default_):
keyboard.write(default_)
return input(prompt_)
if __name__ == "__main__":
print(input_with_default("Please enter: ", "hello world"))

I like this, It works on window
def inputWdefault(prompt, default):
bck = chr(8) * len(default)
ret = input(prompt + default + bck)
return ret or default

I liked the approach taken by #MCO so I refactored the code. I tested it on X Windows and Microsoft Windows 10 WSL 2 using Microsoft Terminal:
def input_with_default(prompt, prefill=''):
try:
from pyautogui import typewrite
print(prompt)
typewrite(prefill)
return input()
except (ImportError, KeyError):
import readline
readline.set_startup_hook(lambda: readline.insert_text(prefill))
try:
return input(prompt)
finally:
readline.set_startup_hook()

Not the best aproach but for the sake of sharing...
You could use Javascript to get all sort of inputs in IPython Notebook.
from IPython.display import HTML
newvar = ""
htm = """
<input id="inptval" style="width:60%;" type="text" value="This is an editable default value.">
<button onclick="set_value()" style="width:20%;">OK</button>
<script type="text/Javascript">
function set_value(){
var input_value = document.getElementById('inptval').value;
var command = "newvar = '" + input_value + "'";
var kernel = IPython.notebook.kernel;
kernel.execute(command);
}
</script>
"""
HTML(htm)
On the next cell you can use the new variable:
print newvar

We can use Tkinter and use a StringVar to do this. The limitation is that the input is through a Tkinter window.
from tkinter import Tk, LEFT, BOTH, StringVar
from tkinter.ttk import Entry, Frame
class Example(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
self.parent = parent
self.initUI()
def initUI(self):
self.parent.title("Entry")
self.pack(fill=BOTH, expand=1)
self.contents = StringVar()
# give the StringVar a default value
self.contents.set('test')
self.entry = Entry(self)
self.entry.pack(side=LEFT, padx=15)
self.entry["textvariable"] = self.contents
self.entry.bind('<Key-Return>', self.on_changed)
def on_changed(self, event):
print('contents: {}'.format(self.contents.get()))
return True
def main():
root = Tk()
ex = Example(root)
root.geometry("250x100+300+300")
root.mainloop()
if __name__ == '__main__':
main()

If you are writing a CLI, you might want to consider using the python-click library for this.
You would achieve your goal with the following code:
import click
user_input = click.prompt(text="Folder name", default="Download")
print(f"{user_input=}")
If you run this code, and type in nothing, then you get:
$ python3 cli_code.py
Folder name [Download]:
user_input='Download'
If you run this code, and type in 'my-dir', then you get:
$ python3 cli_code.py
Folder name [Download]: my-dir
user_input='my-dir'

Try using an "f-string" and "or" combination, say:
default_name = "that_folder"
this_folder = input(f"Folder name: ({default_name}) ") or default_name
print(this_folder)
If you hit Return without typing in the folder name, the default_name will be assumed.

This is not a very Good Answer but it is a work around for windows. As hard as I tried, I could not get Readline or pyReadline to work on my Windows10 computer with Python Ver 3.5. So I wrote this instead. Not the best code in the world since I've only been using Python for 3 months. But it works.
import os
def note_input(defaultvalue):
#Create a textfile
txtfile = open("txtfile.txt", "w")
#
# populate it with the default value
txtfile.write(defaultvalue)
txtfile.close()
#
# call Notepad
os.system("notepad.exe txtfile.txt")
# input("Just holding until notepad is close : ") (did not need this line)
#
# get the Value Entered/Changed in Notepad
txtfile = open("txtfile.txt", "r")
func_value = txtfile.read()
txtfile.close()
return func_value
# END DEF
Notepad stopped the program from running until it was closed, so the input() line below it was not needed. Once notepad was opened the first time and placed where I wanted it on the screen, It was like a popup input window. I assume you can use any text editor like Notepad++ or Scripe or Code Writer, etc.

If you do that, the user would have to delete the existing word. What about providing a default value if the user hits "return"?
>>> default_folder = "My Documents"
>>> try: folder = input("folder name [%s]:" %default_folder)
... except SyntaxError: folder = default_folder