Hi everyone 👋
I’m new to Python and just started learning.
I want to improve my skills and make some coding friends here.
Looking forward to learning from you all 😊
#🔒 #Beginner here – want to learn Python and make friends👀
wary lark
tidal pendantBOT
Hi everyone 👋
I’m new to Python and just started learning.
I want to improv...
@wary lark
Python help channel opened
wary lark
#Beginner here – want to learn Python and make friends👀
bold copper
#❓｜how-to-get-help @wary lark
waxen thicket
Hi everyone 👋
I’m new to Python and just started learning.
I want to improv...
Do you have any particular question at this time?
wary lark
I am confused about if-else statements. Can anyone explain with an example?
waxen thicket
I am confused about if-else statements. Can anyone explain with an example?
Sure.
First, we need to understand that if and elif are looking at exactly one object each. Let's start by looking at if by itself.
!e ```py
if True:
print ("A")
if False:
print("B")```
tidal pendantBOT
!e ```py
if True:
print ("A")
if False:
print("B")```
:white_check_mark: Your 3.14 eval job has completed with return code 0.
A
First, the if looks at the object to its right. If that object is truthy, that if's block is run. We see that A is printed.
True is truthy.
Then we see the next if. It looks at False, which is falsy, and does not print B.
We will often use expressions to form the objects True and False by other means.
!e py print(1 + 1 == 2) print(3 + 4 == 9001)
tidal pendantBOT
!e ```py
print(1 + 1 == 2)
print(3 + 4 == 9001)```
:white_check_mark: Your 3.14 eval job has completed with return code 0.
001 | True
002 | False
!e py name = "Peter" print(name == "Peter") print(name == "Sally")
tidal pendantBOT
!e ```py
name = "Peter"
print(name == "Peter")
print(name == "Sally")```
:white_check_mark: Your 3.14 eval job has completed with return code 0.
001 | True
002 | False
and we can plug these expressions into if and elif
!e ```py
name = "Peter"
if name == "Peter":
print("A")
if name == "Sally":
print("B")```
tidal pendantBOT
!e ```py
name = "Peter"
if name == "Peter":
print("A")
if name == "Sally":
...
:white_check_mark: Your 3.14 eval job has completed with return code 0.
A
elif stands for else, if
An if compound statement us comprised of...py if condition: "Exactly one if" elif some_other_condition: "Zero or more elifs" elif ...: ... # etc else: "Zero or one else"In that order. The first condition to be satisfied has its block run.
!e py if True: print("A") elif True: print("B") else: print("C")
tidal pendantBOT
!e ```py
if True:
print("A")
elif True:
print("B")
else:
print("C")`...
:white_check_mark: Your 3.14 eval job has completed with return code 0.
A
!e py if False: print("A") elif True: print("B") else: print("C")
tidal pendantBOT
!e ```py
if False:
print("A")
elif True:
print("B")
else:
print("C")...
:white_check_mark: Your 3.14 eval job has completed with return code 0.
B
!e py if False: print("A") elif False: print("B") else: print("C")
tidal pendantBOT
!e ```py
if False:
print("A")
elif False:
print("B")
else:
print("C"...
:white_check_mark: Your 3.14 eval job has completed with return code 0.
C
Imagine a deck of cards with conditions. You draw from the top of the deck and stop when you hit a card with a satisfied condition.
That is an if/elif. Else is if you hit the bottom of the deck and exhausted your cards.
!e py if ...: ... "Writing other code here ends the if/elif/else." elif ...: # making this illegal ...
tidal pendantBOT
!e ```py
if ...:
...
"Writing other code here ends the if/elif/else."
elif ....
:x: Your 3.14 eval job has completed with return code 1.
001 | File [35m"/home/main.py"[0m, line [35m4[0m
002 | [1;31melif[0m ...: # making this illegal
003 | [1;31m^^^^[0m
004 | [1;35mSyntaxError[0m: [35minvalid syntax[0m
@wary lark Does this help clarify the matter?
wary lark
@waxen thicket
"Got it! So if/elif checks conditions one by one from the top, and else is the final backup if nothing matches.
waxen thicket
Correct.
!e ```py
if "abc":
print("A")
if "":
print("B")```Empty strings are falsy. Strings of nonzero length are truthy.
tidal pendantBOT
!e ```py
if "abc":
print("A")
if "":
print("B")```Empty strings are fal...
:white_check_mark: Your 3.14 eval job has completed with return code 0.
A
golden grove
@wary lark yep true bro
waxen thicket
!e ```py
if [123]:
print("A")
if []:
print("B")```Lists with things in them are truthy. Empty lists are falsy.
tidal pendantBOT
!e ```py
if [123]:
print("A")
if []:
print("B")```Lists with things in ...
:white_check_mark: Your 3.14 eval job has completed with return code 0.
A
!e ```py
if -1:
print("A")
if 0:
print("B")
if 1:
print("C")```
tidal pendantBOT
!e ```py
if -1:
print("A")
if 0:
print("B")
if 1:
print("C")```
:white_check_mark: Your 3.14 eval job has completed with return code 0.
001 | A
002 | C
Nonzeroes are truthy. Zero is falsy.
while is related to if in that it, too, checks the truthiness of the object to its right.
while condition:
...```and runs the indent or not, depending.
Except that it will run it on repeat while the condition is truthy at the head of the repeat.
Until such time as it is falsy.
wary lark
@waxen thicket Clear! Non-zeros = truthy, zero = falsy. And while follows the same logic.
wary lark
@waxen thicket Thanks for the explanation😊☺
tidal pendantBOT
Python help channel closed for inactivity