Reload modules

Reload modules#

By default, IPython will only read imported modules when their import is mentioned for the first time. But this option allows you to set some specific rules for importing modules. Official documentation.

In essence this extension doles out two magic %autoreload and %aimport:

  • %autoreload - specifies the import mode;

  • %aimport - sets exceptions for %autoreload if they are provided by the current mode.

Note look like you should use the full path to the files if you want to mention them for %aimport.

%autoreload 1/explicit#

Before executing a cell, only modules mentioned with %aimport will be reloaded.

In the following example I:

  • Create two files fun<i> \(i \in {1,2}\), each containing only one function that returns a line like "Original line from fun<i>.py";

  • Import them using the %autoreload explicit magic and mentioning fun1 in %aimport.

  • Call them, and got obvious result - Original line from fun<i>.py;

  • Then change both functions to return New line from fun<i>.py;

  • Call the functions again:

    • Function from fun1 has changed the line;

    • Function from fun2 still has the word Original at the beginning (because it was mentioned in %aimport as module to me reloaded).

%%bash
cat > reloading_modules_files/fun1.py << EOF
def return_line():
    return "Original line from fun1.py"
EOF
cat > reloading_modules_files/fun2.py << EOF
def return_line():
    return "Original line from fun2.py"
EOF

%load_ext autoreload
%autoreload explicit
from reloading_modules_files import fun1, fun2
%aimport reloading_modules_files.fun1

print(fun1.return_line())
print(fun2.return_line())

Original line from fun1.py
Original line from fun2.py

%%bash
cat > reloading_modules_files/fun1.py << EOF
def return_line():
    return "New line from fun1.py"
EOF
cat > reloading_modules_files/fun2.py << EOF
def return_line():
    return "New line from fun2.py"
EOF

print(fun1.return_line())
print(fun2.return_line())

New line from fun1.py
Original line from fun2.py

%autoreload 2/all#

It’s the most common mode for me - reload all modules before running any cell except those mentioned in %aimport.

If you want to exclude some modules from reimport, you should use %aimport -<module name> (the “-” symbol is crucial here).

In the following example I:

  • Create two files fun<i> \(i \in {1,2}\), each containing only one function that returns a line like "Original line from fun<i>.py";

  • Import them using the %autoreload all magic and mentioning fun2 in %aimport.

  • Call them, and got obvious result - Original line from fun<i>.py;

  • Then change both functions to return New line from fun<i>.py;

  • Call the functions again:

    • Function from fun1 has changed the line;

    • Function from fun2 still has the word Original at the beginning (because it was mentioned in %aimport as an exclusion).

%%bash
cat > reloading_modules_files/fun1.py << EOF
def return_line():
    return "Original line from fun1.py"
EOF
cat > reloading_modules_files/fun2.py << EOF
def return_line():
    return "Original line from fun2.py"
EOF

%load_ext autoreload
%autoreload all

from reloading_modules_files import fun1, fun2
%aimport -reloading_modules_files.fun2
print(fun1.return_line())
print(fun2.return_line())

The autoreload extension is already loaded. To reload it, use:
  %reload_ext autoreload
Original line from fun1.py
Original line from fun2.py

%%bash
cat > reloading_modules_files/fun1.py << EOF
def return_line():
    return "New line from fun1.py"
EOF
cat > reloading_modules_files/fun2.py << EOF
def return_line():
    return "New line from fun2.py"
EOF

print(fun1.return_line())
print(fun2.return_line())

New line from fun1.py
Original line from fun2.py
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