PythonDotLand

for n in range(2, 10):
    for x in range(2, n):
        if n % x == 0:
            print(n, 'equals', x, '*', n//x)
            break
    else:
        # loop fell through without finding a factor
        print(n, 'is a prime number')

PythonDotLand

>>> def get_status(error):
...     return 'OK' if not error else 'We have a problem'
...
>>> get_status(error=True)
'We have a problem'
>>> get_status(error=False)
'OK'

PythonDotLand

>>> import sys
>>> l = [1,2,3]
>>> t = (1,2,3)
>>> sys.getsizeof(l)
120
>>> sys.getsizeof(t)
64

PythonDotLand

import subprocess
thedir = input()
>>> result = subprocess.run([f'ls -al {thedir}'], shell=False)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.8/subprocess.py", line 489, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/usr/lib/python3.8/subprocess.py", line 854, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.8/subprocess.py", line 1702, in _execute_child

PythonDotLand

import subprocess
thedir = input()
# Don't do this:
result = subprocess.run([f'ls -al {thedir}'], shell=True)

PythonDotLand

>>> import subprocess
>>> result = subprocess.run(['ls -al | head -n 1'], shell=True)
total 396
>>> result
CompletedProcess(args=['ls -al | head -n 1'], returncode=0)

PythonDotLand

>>> import subprocess
>>> subprocess.run(['ls', '-al'])

(a list of your directories will be printed)

PythonDotLand

>>> import subprocess
>>> code = """
... for i in range(1, 3):
...   print(f"Hello world {i}")
... """

>>> result = subprocess.run(['python3'], input=code, capture_output=True, encoding='UTF-8')
>>> print(result.stdout)
>>> print(result.stdout)
Hello world 1

PythonDotLand

>>> import subprocess
>>> result = subprocess.run(['python3', '--version'], capture_output=True, encoding='UTF-8')
>>> result
CompletedProcess(args=['python3', '--version'], returncode=0, stdout='Python 3.8.5\n', stderr='')

PythonDotLand

>>> import subprocess
>>> result = subprocess.run(['python3', '--version'])
Python 3.8.5
>>> result
CompletedProcess(args=['python3', '--version'], returncode=0)