Import Python Script Into Another?

Question

I'm going through Zed Shaw's Learn Python The Hard Way and I'm on lesson 26. In this lesson we have to fix some code, and the code calls functions from another script. He says that we don't have to import them to pass the test, but I'm curious as to how we would do so.

Link to the lesson | Link to the code to correct

And here are the particular lines of code that call on a previous script:

words = ex25.break_words(sentence)
sorted_words = ex25.sort_words(words)

print_first_word(words)
print_last_word(words)
print_first_word(sorted_words)
print_last_word(sorted_words)
sorted_words = ex25.sort_sentence(sentence)
print sorted_words
print_first_and_last(sentence)
print_first_a_last_sorted(sentence)

Code to Correct:

This is the code from the course, that's being referenced
- Do not edit the question to correct the code

def break_words(stuff):
    """This function will break up words for us."""
    words = stuff.split(' ')
    return words

def sort_words(words):
    """Sorts the words."""
    return sorted(words)

def print_first_word(words)
    """Prints the first word after popping it off."""
    word = words.poop(0)
    print word

def print_last_word(words):
    """Prints the last word after popping it off."""
    word = words.pop(-1
    print word

def sort_sentence(sentence):
    """Takes in a full sentence and returns the sorted words."""
    words = break_words(sentence)
    return sort_words(words)

def print_first_and_last(sentence):
    """Prints the first and last words of the sentence."""
    words = break_words(sentence)
    print_first_word(words)
    print_last_word(words)

def print_first_and_last_sorted(sentence):
    """Sorts the words then prints the first and last one."""
    words = sort_sentence(sentence)
    print_first_word(words)
    print_last_word(words)


print "Let's practice everything."
print 'You\'d need to know \'bout escapes with \\ that do \n newlines and \t tabs.'

poem = """
\tThe lovely world
with logic so firmly planted
cannot discern \n the needs of love
nor comprehend passion from intuition
and requires an explantion
\n\t\twhere there is none.
"""


print "--------------"
print poem
print "--------------"

five = 10 - 2 + 3 - 5
print "This should be five: %s" % five

def secret_formula(started):
    jelly_beans = started * 500
    jars = jelly_beans \ 1000
    crates = jars / 100
    return jelly_beans, jars, crates


start_point = 10000
beans, jars, crates == secret_formula(start-point)

print "With a starting point of: %d" % start_point
print "We'd have %d jeans, %d jars, and %d crates." % (beans, jars, crates)

start_point = start_point / 10

print "We can also do that this way:"
print "We'd have %d beans, %d jars, and %d crabapples." % secret_formula(start_pont


sentence = "All god\tthings come to those who weight."

words = ex25.break_words(sentence)
sorted_words = ex25.sort_words(words)

print_first_word(words)
print_last_word(words)
.print_first_word(sorted_words)
print_last_word(sorted_words)
sorted_words = ex25.sort_sentence(sentence)
prin sorted_words

print_irst_and_last(sentence)

   print_first_a_last_sorted(senence)

jedwards · Accepted Answer · 2019-10-06T23:43:34.880

131

It depends on how the code in the first file is structured.

If it's just a bunch of functions, like:

# first.py
def foo(): print("foo")
def bar(): print("bar")

Then you could import it and use the functions as follows:

# second.py
import first

first.foo()    # prints "foo"
first.bar()    # prints "bar"

or

# second.py
from first import foo, bar

foo()          # prints "foo"
bar()          # prints "bar"

or, to import all the names defined in first.py:

# second.py
from first import *

foo()          # prints "foo"
bar()          # prints "bar"

Note: This assumes the two files are in the same directory.

It gets a bit more complicated when you want to import names (functions, classes, etc) from modules in other directories or packages.

edited Oct 06 '19 at 23:43

answered Mar 29 '13 at 02:37

jedwards

29,432
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1

Ah, so they just have to be in the same directory... awesome! Thank you! – astroblack Apr 01 '13 at 02:11
8

How does this change for Python 3? – Brian Apr 27 '17 at 16:14
What symbols aren't imported by the first method? – JobHunter69 Jul 17 '17 at 00:01
@Goldname in the first method the *only* symbol imported (into the importer's global namespace) is `first`. In the second, it's `foo` and `bar`. In the third, it's *all* symbols (with some caveats, but notably including any imports that first.py contained). – jedwards Aug 04 '17 at 20:12
2

Maybe useful: it won't work if you use "import first.py" (instead of "import first"). – Pablo Mar 07 '18 at 08:53
One thing to also consider, if there are any library or packages imported in the first.py and they are not already installed in the env you are working, apparently it will fail, but might not be obvious to track the error – MehranYazdizadeh May 18 '20 at 15:19

score 30 · Answer 2 · edited Nov 18 '14 at 13:12

30

It's worth mentioning that (at least in python 3), in order for this to work, you must have a file named __init__.py in the same directory.

edited Nov 18 '14 at 13:12

Edward Anderson

13,591
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answered Sep 10 '14 at 11:24

soungalo

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@LoveMeow Yes, no problem. http://stackoverflow.com/questions/448271/what-is-init-py-for – soungalo Nov 10 '15 at 11:43
8

this is actually not the case for me. It works just fine without it – Ma0 Aug 30 '16 at 11:48
19

If your script (the one you're running) and the file you're importing from are in the same directory, you *do not* need an `__init__.py` file. If your script is *outside* the directory containing the file you're importing, then you would need such a file. – jedwards Aug 04 '17 at 20:14
3

Update to previous comment, [PEP 420](https://www.python.org/dev/peps/pep-0420/) / Python3.3 introduced "Implicit Namespace Packages", obviating the need for empty `__init__.py` files in many cases. – jedwards Oct 06 '19 at 23:41

score 9 · Answer 3 · answered Sep 14 '18 at 08:39

9

Following worked for me and it seems very simple as well:

Let's assume that we want to import a script ./data/get_my_file.py and want to access get_set1() function in it.

import sys
sys.path.insert(0, './data/')
import get_my_file as db

print (db.get_set1())

answered Sep 14 '18 at 08:39

devil in the detail

2,905
17
15

I don´t know why, but this is the only way to make it work, at least for me. – Sidonai Jan 28 '19 at 19:21

score 2 · Answer 4 · edited Feb 04 '20 at 09:39

I highly recommend the reading of a lecture in SciPy-lectures organization:

https://scipy-lectures.org/intro/language/reusing_code.html

It explains all the commented doubts.

But, new paths can be easily added and avoiding duplication with the following code:

import sys
new_path = 'insert here the new path'

if new_path not in sys.path:
    sys.path.append(new_path)
import funcoes_python #Useful python functions saved in a different script

score 0 · Answer 5 · answered Apr 23 '19 at 10:44

Hope this work

def break_words(stuff):
    """This function will break up words for us."""
    words = stuff.split(' ')
    return words

def sort_words(words):
    """Sorts the words."""
    return sorted(words)

def print_first_word(words):
    """Prints the first word after popping it off."""
    word = words.pop(0)
    print (word)

def print_last_word(words):
    """Prints the last word after popping it off."""
    word = words.pop(-1)
    print(word)

def sort_sentence(sentence):
    """Takes in a full sentence and returns the sorted words."""
    words = break_words(sentence)
    return sort_words(words)

def print_first_and_last(sentence):
    """Prints the first and last words of the sentence."""
    words = break_words(sentence)
    print_first_word(words)
    print_last_word(words)

def print_first_and_last_sorted(sentence):
    """Sorts the words then prints the first and last one."""
    words = sort_sentence(sentence)
    print_first_word(words)
    print_last_word(words)


print ("Let's practice everything.")
print ('You\'d need to know \'bout escapes with \\ that do \n newlines and \t tabs.')

poem = """
\tThe lovely world
with logic so firmly planted
cannot discern \n the needs of love
nor comprehend passion from intuition
and requires an explantion
\n\t\twhere there is none.
"""


print ("--------------")
print (poem)
print ("--------------")

five = 10 - 2 + 3 - 5
print ("This should be five: %s" % five)

def secret_formula(start_point):
    jelly_beans = start_point * 500
    jars = jelly_beans / 1000
    crates = jars / 100
    return jelly_beans, jars, crates


start_point = 10000
jelly_beans, jars, crates = secret_formula(start_point)

print ("With a starting point of: %d" % start_point)
print ("We'd have %d jeans, %d jars, and %d crates." % (jelly_beans, jars, crates))

start_point = start_point / 10

print ("We can also do that this way:")
print ("We'd have %d beans, %d jars, and %d crabapples." % secret_formula(start_point))


sentence = "All god\tthings come to those who weight."

words =  break_words(sentence)
sorted_words =  sort_words(words)

print_first_word(words)
print_last_word(words)
print_first_word(sorted_words)
print_last_word(sorted_words)
sorted_words =  sort_sentence(sentence)
print (sorted_words)

print_first_and_last(sentence)
print_first_and_last_sorted(sentence)

Import Python Script Into Another?

Code to Correct:

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