Functions in other files - python

How can I use functions that I have created before, in different python files and projects? for example functions that I have created in project A I want to use in project B.

You need to import like any other library you import in your python file. For example if you have a python script A.py and you are writing another python script B.py and you want to use some methods of A then you just need to import like this:
from A import *
Will import all the methods of A.
you can import a specific method only like this:
from A import method1
Thanks hope it helps

A.py contains
def myFunction():
print("Hello World")
you can call this function in your B.py
by simply importing it
B.py contains
import A
A.myFunction()

Related

Importing python modules from another directory

I am trying to import files (python files) from another directory but it is not working as I have tried.
/pythonproject
.main.py
.__init__.py
->folder1
->.file1.py
->.file2.py
->.__init__.py
->folder2
->.functions.py
->.globals.py
->.__init__.py
I am trying to import functions.py inside of my file2.py.
I have tried
from functions import *
import functions
#file2.py
sys.path.insert(0, '/pythonproject')
import functions
I think your friend for this case is sys.path.append.
As discovered the problem is that you are importing the file, but when you went to use a function in the file you couldn't
One solution is:
import functions
functions.NameOfFunctionHere()

Heroku Python import local functions

I'm developing a chatbot using heroku and python. I have a file fetchWelcome.py in which I have written a function. I need to import the function from fetchWelcome into my main file.
I wrote from fetchWelcome import fetchWelcome in main file. But because we need to mention all the dependencies in the requirement file, it shows error. I don't know how to mention user defined requirement.
How can I import the function from another file into the main file ? Both the files ( main.py and fetchWelcome.py ) are in the same folder.
You're quite close to the answer to the question. Importing works like this:
fetchWelcome.py:
def foo():
# Do something here
print("Hello World")
def bar():
# Do something else
print("Python")
main.py:
import fetchWelcome
fetchWelcome.foo()
fetchWelcome.bar()
If you only want to import a single function, use
from fetchWelcome import foo
foo()
Both files have to be in the same folder.
If we need to import function from fileName into main.py, write
from .fileName import functionName
Thus we don't need to write any dependency in requirement file.

Imported function not working

I am pretty new to Python and am trying to import a function I have made in a separate file. When I run the code I get "TypeError: signal() missing 1 required positional argument: 'handler'". I think it means the signal function is not being passed a single argument but I am pretty sure that is what the for loop does. Where am I going wrong? Also, the files are in the same folder, which is a part of the working directory. The code that calls the function is:
import numpy as np
t=np.linspace(-5,5,200)
import signal
y=[]
for i in t:
y.append(signal.signal(i))
The function code is saved in a file called signal.py. The code is:
def signal(t):
import numpy as np
y=np.cos(t)*np.exp(-abs(t))
return y
It seems you are trying to import a signal from the standard library instead of your own file. Try to import it like this:
from .signal import signal
PS: Since you are new to Python, you should also make sure you have a an __init__.py file in the directory, like so:
/Parent
__init__.py
main.py
signal.py
As suggested by chepner, you have a module name conflict with pythons inbuilt module signal
If the name is not important, then you could change the name.
If the name is important then you could create a package and place the file in that, Then import it.
For example, following will be your directory tree
signal_module/
├── __init__.py
└── signal.py
original_file.py
Then import the signal_module as follows
from signal_module import signal
The __init__.py file is import.
It can be empty, but it needs to be created for python to tree the directory as package.
As you said you are new to python, have a look at this answer to know more about the importance of __init__.py

Python imported module dependency

Let's say I have file main.py :
import math
import mymodule.py
print(math.ceil(5/3))
and then mymodule.py :
print(math.ceil(10/3))
mymodule.py gives an error that math is not defined, even though its parent module has it imported.
Considering both main.py and mymodule.py need to use the math lib, do I need to import it twice? It just seems non-optimal. What's the most pythonic way to solve this issue?
I know it's a dumb example, but I'm trying to fragment a code I made into several modules for organization, and this issue appeared multiple times in several levels
mymodule.py is parent for main.py since you are importing mymodule within main.
You need to import math within mymodule so that it gets inherited in main.
Then there won't be a need to import within main.
mymodule.py
import math
main.py
import mymodule
print mymodule.math.pow(10,2)
Result:
>>>
100.0
>>>
This is really very basic. If you have something in a separate file, like mymodule.py, then you can import that function in any python file easily in the same directory.
two files:
mymodule.py:
import math
def aFunc():
return math.ceil(10/3)
# We could also just use this file as a standalone
if __name__ == "__main__":
print(aFunc())
main.py:
import mymodule
print(mymodule.aFunc())
You could also specifically call out the function you want to import.
main.py (alternative):
from mymodule import aFunc
print(aFunc())

How do I call a function from another .py file? [duplicate]

This question already has answers here:
How do I import other Python files?
(23 answers)
Closed 6 months ago.
file.py contains a function named function. How do I import it?
from file.py import function(a,b)
The above gives an error:
ImportError: No module named 'file.py'; file is not a package
First, import function from file.py:
from file import function
Later, call the function using:
function(a, b)
Note that file is one of Python's core modules, so I suggest you change the filename of file.py to something else.
Note that if you're trying to import functions from a.py to a file called b.py, you will need to make sure that a.py and b.py are in the same directory.
Do not write .py when importing.
Let file_a.py contain some functions inside it:
def f():
return 1
def g():
return 2
To import these functions into file_z.py, do this:
from file_a import f, g
If your file is in the different package structure and you want to call it from a different package, then you can call it in that fashion:
Let's say you have following package structure in your python project:
in - com.my.func.DifferentFunction python file you have some function, like:
def add(arg1, arg2):
return arg1 + arg2
def sub(arg1, arg2) :
return arg1 - arg2
def mul(arg1, arg2) :
return arg1 * arg2
And you want to call different functions from Example3.py, then following way you can do it:
Define import statement in Example3.py - file for import all function
from com.my.func.DifferentFunction import *
or define each function name which you want to import
from com.my.func.DifferentFunction import add, sub, mul
Then in Example3.py you can call function for execute:
num1 = 20
num2 = 10
print("\n add : ", add(num1,num2))
print("\n sub : ", sub(num1,num2))
print("\n mul : ", mul(num1,num2))
Output:
add : 30
sub : 10
mul : 200
Method 1. Import the specific function(s) you want from file.py:
from file import function
Method 2. Import the entire file:
import file as fl
Then, to call any function inside file.py, use:
fl.function(a, b)
Note: If you are working with Jupiter notebook you may need to change path for method 1. :
os.chdir('/')
see https://stackoverflow.com/a/35665295/1984636
And for method 2:
import sys
sys.path.append('../src/')
see https://stackoverflow.com/a/55623567/1984636
You can call the function from a different directory as well, in case you cannot or do not want to have the function in the same directory you are working. You can do this in two ways (perhaps there are more alternatives, but these are the ones that have worked for me).
Alternative 1
Temporarily change your working directory
import os
os.chdir("**Put here the directory where you have the file with your function**")
from file import function
os.chdir("**Put here the directory where you were working**")
Alternative 2
Add the directory where you have your function to sys.path
import sys
sys.path.append("**Put here the directory where you have the file with your function**")
from file import function
To fix
ModuleNotFoundError: No module named
try using a dot (.) in front of the filename to do a relative import:
from .file import function
Functions from .py file (can (of course) be in different directory) can be simply imported by writing directories first and then the file name without .py extension:
from directory_name.file_name import function_name
And later be used: function_name()
Rename the module to something other than 'file'.
Then also be sure when you are calling the function that:
1)if you are importing the entire module, you reiterate the module name when calling it:
import module
module.function_name()
or
import pizza
pizza.pizza_function()
2)or if you are importing specific functions, functions with an alias, or all functions using *, you don't reiterate the module name:
from pizza import pizza_function
pizza_function()
or
from pizza import pizza_function as pf
pf()
or
from pizza import *
pizza_function()
First save the file in .py format (for example, my_example.py).
And if that file have functions,
def xyz():
--------
--------
def abc():
--------
--------
In the calling function you just have to type the below lines.
file_name: my_example2.py
============================
import my_example.py
a = my_example.xyz()
b = my_example.abc()
============================
append a dot . in front of a file name if you want to import this file which is in the same directory where you are running your code.
For example, I'm running a file named a.py and I want to import a method named addFun which is written in b.py, and b.py is there in the same directory
from .b import addFun
Inside MathMethod.Py.
def Add(a,b):
return a+b
def subtract(a,b):
return a-b
Inside Main.Py
import MathMethod as MM
print(MM.Add(200,1000))
Output:1200
You don't have to add file.py.
Just keep the file in the same location with the file from where you want to import it. Then just import your functions:
from file import a, b
Solution1: In one file myfun.py define any function(s).
# functions
def Print_Text():
print( 'Thank You')
def Add(a,b):
c=a+b
return c
In the other file:
#Import defined functions
from myfun import *
#Call functions
Print_Text()
c=Add(1,2)
Solution2: if this above solution did not work for Colab
Create a foldermyfun
Inside this folder create a file __init__.py
Write all your functions in __init__.py
Import your functions from Colab notebook from myfun import *
You should have the file at the same location as that of the Python files you are trying to import. Also 'from file import function' is enough.
Any of the above solutions didn't work for me. I got ModuleNotFoundError: No module named whtever error.
So my solution was importing like below
from . import filename # without .py
inside my first file I have defined function fun like below
# file name is firstFile.py
def fun():
print('this is fun')
inside the second file lets say I want to call the function fun
from . import firstFile
def secondFunc():
firstFile.fun() # calling `fun` from the first file
secondFunc() # calling the function `secondFunc`
Suppose the file you want to call is anotherfile.py and the method you want to call is method1, then first import the file and then the method
from anotherfile import method1
if method1 is part of a class, let the class be class1, then
from anotherfile import class1
then create an object of class1, suppose the object name is ob1, then
ob1 = class1()
ob1.method1()
in my case i named my file helper.scrap.py and couldn't make it work until i changed to helper.py
in my main script detectiveROB.py file i need call passGen function which generate password hash and that functions is under modules\passwordGen.py
The quickest and easiest solution for me is
Below is my directory structure
So in detectiveROB.py i have import my function with below syntax
from modules.passwordGen import passGen
Just a quick suggestion,
Those who believe in auto-import by pressing alt+ enter in Pycharm and cannot get help.
Just change the file name from where you want to import by:
right-clicking on the file and clicking on refactor-> rename.
Your auto-import option will start coming up

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