Python:Control structures: Difference between revisions

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for var1 in itterable:  # keys if itterable is a dict
for var1 in itterable:  # keys if itterable is a dict
    block
    if somethinghappens:
        break<syntaxhighlight lang=python>
while expression:
     block
     block
     if somethinghappens:
     if somethinghappens:
Line 21: Line 26:
;<code>pass</code>
;<code>pass</code>
:No operation, use e.g. to avoid negative tests
:No operation, use e.g. to avoid negative tests
;Sleep function
<syntaxhighlight lang=python>
import time
time.sleep(<sec>)
</syntaxhighlight>


==Exception handling==
==Exception handling==

Revision as of 18:50, 24 October 2020


Most flow control is standard. Indentation defines the code block to execute. You must be strict, all indents must be the same in a block, a mix of spaces and tabs is not allowed (unless each line uses the same mix).

You can define you own Python:Functions too.

if expression:
    block
elif expression:
    block
else:
    otherblock

for var1 in itterable:  # keys if itterable is a dict
    block
    if somethinghappens:
        break<syntaxhighlight lang=python>

while expression:
    block
    if somethinghappens:
        break
pass
No operation, use e.g. to avoid negative tests
Sleep function
import time
time.sleep(<sec>)


Exception handling

To catch exceptions:

try:
    blockthatmaythowexception
except <exception>:
    blockifexceptionisthrown
else:
    blockifNOexceptionisthrown

Specifying an exception is optional but highly recommended. The exceptiontypes can be found in the python docs

except NameError
The variable does not exist
except KeyError
The key does not exist in the dict
except IndexError
The index does not exist in the list