Npm Javascript
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Michael Zippo
04.11.2021
Npm (package manager node) helps focus on JavaScript developers code rather than other - sometimes boring and repetitive - details. Sometimes, however, you may come across MNP errors like NPM not found command.
We will be working on how to correct this error so you can get back to enjoying everything NPM has to offer.
What is the NPM not found error command?
The Npm not found command error may appear while installing or upgrading NPM.
In Windows, the cause of this error could be that a PATH or SYSTEM variable is not set correctly. The error can also occur if you don’t have NPM or Node.js installed, have an outdated version, or have permission issues.
Mac users who see NPM command error may not be found due to a missing files on your computer or a permissions issue.
This article discusses these reasons. First we will cover general installation related causes, then we will get into Mac specific solutions, before we get to how to fix a potential missing PATH variable on Windows.
Check if NPM is installed
The NPM command requires NPM to be installed on Windows. NPM uses Node.js, so it is included in the Node.js installation package. To check if you have installed Node.js type the following command in the terminal:
-v stands for "version". Visit the NPM site to check if the NPM version you have installed is the one Latest Version
You have no doubt accidentally deleted your NPM file or moved its location. This can happen more often than you think, especially if you change your path on your system
Check if NPM is installed as well as the node by typing in your terminal:
If NPM is installed, the version on your computer will be displayed To install NPM, run the commands here for Mac and here if you are using windows .
Update NPM
Also, if NPM comes with Node.js they are separate meaning you can have the latest one and not the other because they may have update release dates .
If you have a node (check with node $ -v) and your node working, you just need to update NPM. The last day of NPM can be done with a single line:
If you have any problems with this command, you may - be made -the precede sudo :
If you are working on your code block -code block in an editor, be sure to restart it after you have finished installing or upgrading
you may still see command NPM not found because the C: .. Program Files odejs may not be present in the PATH environment variable
- Open global search Ôîé and search for " environment variables ".
- Choose "Edit environment system variables ".
- Click on "environment" in the "Advanced" tab
- In the "System Variables" box, locate the path and modify it to include the path C: Program Files ODEJ s. If you do n’t see it, click on "New" then add this path. (Note: Depending on your version, you simply need to edit and add the path to what is present by prefixing with a point - point you will see that other paths are separated by dots - commas ..) < / Li>
Here are some documents on windows settings and NPM related environment variables in case you are curious and want to know more about the settings.
Solution for permissions
for permission issues, precede terminal commands with sudo ignore issues. Authorization issues can be the cause of the inability to properly download program files. You can also try the following terminal commands as a last resort if all others haven’t worked for you, although this may not be an option for you if you are on a shared or work computer for Mac and Linux users.:.
This command allows to set the permissions of NPM folder . Chown means change owner, R means recursive (in all files it contains), "whoami" takes your user account name and the last line is the where you want to find the node package files. After running the above command , try the NPM command you try again.
Conclusion
After setting implement change, we moved on to troubleshoot the "command not found" error, make - to restart an open code editor or a terminal / quick order. To sum up, the suggested solutions we talked about were as follows:
- Update NPM
- check if node is up to date
- fix the PATH under Windows
- change permissions for the node
this article contains educational links on how to uninstall and install NPM for Windows or Mac. If you can do this you can remove any blocks that NPM is having.
If you want to know more about NPM, read this article on NPM which includes resources and proven to curated in know more.
Npm Javascript __del__: Questions
How can I make a time delay in Python?
5 answers
I would like to know how to put a time delay in a Python script.
2973
Answer #1
import time
time.sleep(5) # Delays for 5 seconds. You can also use a float value.
Here is another example where something is run approximately once a minute:
import time
while True:
print("This prints once a minute.")
time.sleep(60) # Delay for 1 minute (60 seconds).
How to delete a file or folder in Python?
5 answers
How do I delete a file or folder in Python?
2639
Answer #1
Path objects from the Python 3.4+ pathlib module also expose these instance methods:
Npm Javascript __delete__: Questions
2639
Answer #2
Path objects from the Python 3.4+ pathlib module also expose these instance methods:
2639
Answer #3
Python syntax to delete a file
import os
os.remove("/tmp/<file_name>.txt")
Or
import os
os.unlink("/tmp/<file_name>.txt")
Or
pathlib Library for Python version >= 3.4
file_to_rem = pathlib.Path("/tmp/<file_name>.txt")
file_to_rem.unlink()
Path.unlink(missing_ok=False)
Unlink method used to remove the file or the symbolik link.
If missing_ok is false (the default), FileNotFoundError is raised if the path does not exist.
If missing_ok is true, FileNotFoundError exceptions will be ignored (same behavior as the POSIX rm -f command).
Changed in version 3.8: The missing_ok parameter was added.
Best practice
- First, check whether the file or folder exists or not then only delete that file. This can be achieved in two ways :
a. os.path.isfile("/path/to/file")
b. Use exception handling.
EXAMPLE for os.path.isfile
#!/usr/bin/python
import os
myfile="/tmp/foo.txt"
## If file exists, delete it ##
if os.path.isfile(myfile):
os.remove(myfile)
else: ## Show an error ##
print("Error: %s file not found" % myfile)
Exception Handling
#!/usr/bin/python
import os
## Get input ##
myfile= raw_input("Enter file name to delete: ")
## Try to delete the file ##
try:
os.remove(myfile)
except OSError as e: ## if failed, report it back to the user ##
print ("Error: %s - %s." % (e.filename, e.strerror))
RESPECTIVE OUTPUT
Enter file name to delete : demo.txt
Error: demo.txt - No such file or directory.
Enter file name to delete : rrr.txt
Error: rrr.txt - Operation not permitted.
Enter file name to delete : foo.txt
Python syntax to delete a folder
shutil.rmtree()
Example for shutil.rmtree()
#!/usr/bin/python
import os
import sys
import shutil
# Get directory name
mydir= raw_input("Enter directory name: ")
## Try to remove tree; if failed show an error using try...except on screen
try:
shutil.rmtree(mydir)
except OSError as e:
print ("Error: %s - %s." % (e.filename, e.strerror))
Is there a simple way to delete a list element by value?
5 answers
I want to remove a value from a list if it exists in the list (which it may not).
a = [1, 2, 3, 4]
b = a.index(6)
del a[b]
print(a)
The above case (in which it does not exist) shows the following error:
Traceback (most recent call last):
File "D:zjm_codea.py", line 6, in <module>
b = a.index(6)
ValueError: list.index(x): x not in list
So I have to do this:
a = [1, 2, 3, 4]
try:
b = a.index(6)
del a[b]
except:
pass
print(a)
But is there not a simpler way to do this?
1055
Answer #1
To remove an element"s first occurrence in a list, simply use list.remove:
>>> a = ["a", "b", "c", "d"]
>>> a.remove("b")
>>> print(a)
["a", "c", "d"]
Mind that it does not remove all occurrences of your element. Use a list comprehension for that.
>>> a = [10, 20, 30, 40, 20, 30, 40, 20, 70, 20]
>>> a = [x for x in a if x != 20]
>>> print(a)
[10, 30, 40, 30, 40, 70]
