That’s one of the problems with Python. Blocks of code are defined by their indentation position.
That’s a pain when you copy and past and the IDE reindents the code thinking that is doing great, or generate a new inner class instead of replacing all the code.
Well, this error is very annoying cause it means that you mixed spaces and Tabs as indent separators.
But you can go crazy trying to find a tab in your code, so there is a trick that I came with:
Basically go to Menu Edit > Find and then type 4 times space. PyCharm will highlight all the places were this indentation (4 spaces) is present, so you’ll find the impostor without going blind or losing to many time.
As you can see, in front of def execute_command_without_waiting we don’t have 4 spaces. And in this case the impostor was not a camouflaged tab \t but 3 spaces instead of four.
If you are using Git Submodules, is very probable that at some point you will create you own libraries. Probably those libraries will have their own structure, even with their own tests/ folder and you’re adding into a subfolder into your new project and maybe you have problems using relative imports.
This is a trick you can use to add the relevant root folder of your project to the System Path, so the libraries are found, specially when you call by command line from anywhere in the filesystem. This works for Python2 and Python3.
#!/usr/bin/env python3
import sys
import os
s_path_program = os.path.dirname(__file__)
sys.path.append(s_path_program + '../../')
from clib.src.argsutils import ArgsUtils
from clib.src.datetimeutils import DateTimeUtils
from clib.src.fileutils import FileUtils
I wanted to automate certain operations that we do very often, and so I decided to do a PoC of how handy will it be to create GUI applications that can automate tasks.
As locating information in several repositories of information (ldap, databases, websites, etc…) can be tedious I decided to create a small program that queries LDAP for the information I’m interested, in this case a Location. This small program can very easily escalated to launch the VPN, to query a Database after querying LDAP if no results are found, etc…
I share with you the basic application as you may find interesting to create GUI applications in Python, compatible with Windows, Linux and Mac.
I’m super Linux fan but this is important, as many multinationals still use Windows or Mac even for Engineers and SRE positions.
With the article I provide a Dockerfile and a docker-compose.yml file that will launch an OpenLDAP Docker Container preloaded with very basic information and a PHPLDAPMIN Container.
After some work reviewing it and ensuring it has the expected quality, I finally published my book Python Combat Guide.
Is an atypical creation. Is more a Master Class to my best friend, it could be a SDM, TL leading a small Software Development department, a Coder or a Scientist wanting to join IT as programmer and to learn a lot of stuff very quickly, than rather a formal Python Book for learning. Absolutely is not for beginners.
If you want to buy it, to explore the TOC, extended description…
If you see the Official Python3 documentation for strip(), it says that strip without parameters will return the string without the leading and trailing white spaces.
Optionally you can pass a string with the characters you want to eliminate.
The official documentation for Python 2 says:
string.strip(s[, chars])
Return a copy of the string with leading and trailing characters removed. If chars is omitted or None, whitespace characters are removed. If given and not None, chars must be a string; the characters in the string will be stripped from the both ends of the string this method is called on.
Changed in version 2.2.3: The chars parameter was added. The chars parameter cannot be passed in earlier 2.2 versions.
A white space is a white space. Is not an Enter.
But strip() without parameters will remove white spaces (space), and Enter \n and Tabs \t.
Probably you will not realize that unless you read from a file that has empty lines at the end for a reason, and you use strip().
You can see a demonstration following this small program, that runs the same for Python2 and Python3.
And the corresponding output for python2 and python3:
The [ ] characters where added to show that there are no hidden tabs or similar after.
Here I paste the code so you can try yourself:
import sys
def print_bar():
print("-----------------------------------------------------")
def print_between_brackets(s_test):
print("[" + s_test + "]")
s_string_with_enters = " Testing strip not only removing white spaces, but Enter and Tabs s well\n\t\n\n"
print("Testing .strip()")
print("You are running Python " + sys.version)
print("This is the original string")
print_bar()
print_between_brackets(s_string_with_enters)
print_bar()
print("Now after strip()...")
print_bar()
print_between_brackets(s_string_with_enters.strip())
print_bar()
print("As you can see the Enters and the Tabs have been removed, not just the spaced")
I think this should be disambiguate so I decided to take action. Is very easy to blame and never contribute. Not me. I went to Python to fix that and I located a bug reporting this issue:
The issue was registed and made specially interesting contributions by Dimitri Papadopoulos Orfanos.
The thread is really interesting to read. I recommend it.
At a glance:
“Python heavily relies on isspace() to detect “whitespace” characters.”
* Lib/string.py near line 23:
whitespace = ' \t\n\r\v\f'
So all those characters will be stripped in Python2.7 if you use just string.strip()
The ticket was opened the 2015-10-18 12:15. So it’s a shame the documentation has not been updated yet, more than 3 years later. Those are the kind of things, lack of care, that I can’t understand. Not looking for the excellence.
Please, do note that Python3 supports Unicode natively and things are always a bit different than with Python2 and AscII.
I lead a project where I decided to go with Python 2.7, for the wide compatibility across all the Servers around.
With RHEL now supporting Python 3 as well, it doesn’t make much sense any more, as all the major brands do support Python 3 directly.
I saw it coming so in my Coding Style Guide for my Team I explained that we will use print(“”) which is the required way to proceed with Python 3, as opposite to print “whatever” from Python 2. Noye Python 2 supports both methods.
But today something unexpected appeared in the Tests. One line of code was making a print of ().
The line of code was:
print()
And not
print("")
And the curiosity is that if you do print() in Python 2.7 it outputs ().
Please, take in count that the colors may be different depending on the Terminal used, so if you’re creating a commercial application I recommend you to try with some of them like: ubuntu terminal, ssh, putty for windows, MobaXTerm…
View from the colors from the Console of PyCharm Community Edition
