Karën Fort (CC BY-NC-SA) -- 2024
🥳 What do you already know about strings?
Strings are declared using double quotes or single quotes:
my_string = "saperlipopette !"
my_other_string = 'pouet'
print(my_string)
print(my_other_string)
saperlipopette ! pouet
If you need to include quotes in your string, use the other type of quote
chaine = "This is a 'new' string"
print(chaine)
This is a 'new' string
🆕 you can write a multiple line string with three quotes:
bella = '''Una mattina mi sono alzato
O bella ciao, bella ciao, bella ciao ciao ciao
Una mattina mi sono alzato
E ho trovato l'invasor'''
print(bella)
Una mattina mi sono alzato O bella ciao, bella ciao, bella ciao ciao ciao Una mattina mi sono alzato E ho trovato l'invasor
Strings are in Unicode, which means you can represent any language
my_chinese_string = "猫" #the word "cat" in simplified Chinese (according to Google translate)
print(my_chinese_string)
猫
Strings in Python are arrays of bytes.
This means you can access a character of a string like an element in an array.
We'll see soon that we can iterate on a string
poppins_string = "superfragilistiexpialidocious"
print(poppins_string[1])
u
and yes, do not forget that Python counts from 0! (you will forget, but keep that in mind)
You already know one of them:
len: returns the size of the stringprint(len(poppins_string))
29
There are also a lot of methods (see here), here are some of them:
print(poppins_string.upper()) #note the difference of syntax: len(x) vs x.upper(), we'll come back to it later
SUPERFRAGILISTIEXPIALIDOCIOUS
print(poppins_string.capitalize())
Superfragilistiexpialidocious
Note that some methods take parameters:
trouve = "We will rock you!"
found = trouve.find("rock")#finds the first occurrence of the specified value
print(found)
not_found = trouve.find("show")#returns -1 if not found
print(not_found)
8 -1
song = "only our rivers run free"
final = song.replace("rivers", "people")
print(final)
only our people run free
🥳 Replace "alzato" by "svegliato" in bella:
bella = '''Una mattina mi sono alzato
O bella ciao, bella ciao, bella ciao ciao ciao
Una mattina mi sono alzato
E ho trovato l'invasor'''
# Code Me!
⚠️ Strings are immutable
This means they cannot be modified, once created.
first_string = "Hello, world!"
first_string[0] = "V" #trying to modify the array
print(first_string)
--------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-19-e396701c91c2> in <module> 1 first_string = "Hello, world!" ----> 2 first_string[0] = "V" #trying to modify the array 3 4 print(first_string) TypeError: 'str' object does not support item assignment
However, you can modify the reference to the string:
song = "only our rivers run free"
song = song.replace("rivers", "people")
print(song)
only our people run free
print()¶By default, the print() function adds a newline character \n at the end of the output.
print("this is a")
print("test")
this is a test
print() can take several parameters and concatenates them with spaces:
import math #you need this to use pi
pi = math.pi
print("The value of pi is", pi,"!")#here, print is used with 3 parameters of different types
The value of pi is 3.141592653589793 !
if instruction¶Theif operator introduces a block of code which will be executed if and only if the expressed condition is met:
answer = input("Do you feel ok?")
if "no" in answer: # note the ":"!
print("Poor dear! What's wrong?") # note the indentation!
Do you feel ok?yes
if "yes" in answer:
print("Cool!")
Cool!
if can be included in ifs:
answer = input("how old are you?")
if int(answer) > 50: # note int() to change the type of the answer
if int(answer) > 70:
print("Ok, boomer!") # this print() depends on the "so bad" condition
print("So how was it to live the 80s?") # this print() depends only on the first condition
print("Thank you!") # this print() will execute in all cases
how old are you?1 Thank you!
and and or¶and and or are logical operators allowing you to specify (typically) two conditions at the same time:
upper_age = 65
lower_age = 27
my_age = input("What's your age? ")
if int(my_age) < upper_age and int(my_age) > lower_age: # AND: the two conditions have to be met at the same time
print("There is no SNQF reduction available for you, sorry!")
else:
print("In order for you to get your reduction we need a blood sample and a liver biopsy.")
What's your age? 52 There is no SNQF reduction available for you, sorry!
upper_age = 25
upper_revenue = 35000
my_age = input("What's your age?")
my_revenue = input("What's your annual revenue?")
if int(my_age) > upper_age or int(my_revenue) > upper_revenue: # OR: one of the conditions has to be met
print("There is no benefit available for you, sorry!")
else:
print("In order for you to get your benefit we need a blood sample and a liver biopsy.")
What's your age?26 What's your annual revenue?34000 There is no benefit available for you, sorry!
not¶You can negate a condition:
upper_age = 25
my_age = input("What's your age?")
if not int(my_age) > upper_age:
print("You're too young!")
else:
print("You're too old!")
What's your age?52 You're too old!
else instruction¶The else operator introduces a block of code which will be executed if the if condition is not met. else is linked to the preceeding if and does not allow to add a condition:
answer = input("how old are you?")
if int(answer) > 50: # note int() to change the type of the answer
if int(answer) > 70:
print("Ok, boomer!") # this print() depends on the "so bad" condition
print("So how was it to live the 80s?") # this print() depends only on the first condition
else:
print("You're so young!") # this print() will execute only if the > 50 condition is not met
print("Thank you!") # this print() will execute in all cases
how old are you?49 You're so young! Thank you!
elif instruction¶elif is an else with a condition: it checks both that the condition is true and that all the previous conditions are false.
answer = input("how old are you?")
if int(answer) > 50: # note int() to change the type of the answer
if int(answer) > 70:
print("Ok, boomer!") # this print() depends on the "so bad" condition
print("So how was it to live the 80s?") # this print() depends only on the first condition
elif int(answer) > 40:
print("You're older than I thought")
else:
print("You're so young!") # this print() will execute only if none of the previous conditions are met
print("Thank you!") # this print() will execute in all cases
how old are you?45 You're older than I thought Thank you!
for loops¶for loops allow to iterate over elements of containers such as strings, and to access items of those containers individually, in order:
for character in "قطة": # this string means "cat" in standard Arabic (according to Google translate)
print(character)
ق ط ة
Of course, loops and control flow can be mixed:
for character in "قطة": # Note the ":"
if character == "ق":
print("This is the first character:",character)
else:
print(character)
This is the first character: ق ط ة
🥳 Print the number of occurrences of "a" and "e" in the following string (please use for...)
Perec = "Anton Voyl n'arrivait pas à dormir. Il alluma. Son Jaz marquait minuit vingt. Il poussa un profond soupir, s'assit dans son lit, s'appuyant sur son polochon. Il prit un roman, il l'ouvrit, il lut; mais il n'y saisissait qu'un imbroglio confus, il butait à tout instant sur un mot dont il ignorait la signification. "
while loops¶while loops indicate a stopping condition for a loop.
i = 1
while i < 6: # Note the ":"
print(i)
i += 1 # Note this operator, which is equivalent to i = i +1
1 2 3 4 5
🥳 Print the characters of a string using while instead of for (tip: use len)
# CODE ME!
What will happen if i write this (you can interrupt the execution by entering i twice):
while True:
print("spam")
spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam 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spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam 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spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam spam 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--------------------------------------------------------------------------- KeyboardInterrupt Traceback (most recent call last) <ipython-input-1-e61e1f19f6ea> in <module> 1 while True: ----> 2 print("spam") ~/Dev/notebook/jupyterenv/lib/python3.6/site-packages/ipykernel/iostream.py in write(self, string) 400 is_child = (not self._is_master_process()) 401 # only touch the buffer in the IO thread to avoid races --> 402 self.pub_thread.schedule(lambda : self._buffer.write(string)) 403 if is_child: 404 # mp.Pool cannot be trusted to flush promptly (or ever), ~/Dev/notebook/jupyterenv/lib/python3.6/site-packages/ipykernel/iostream.py in schedule(self, f) 201 self._events.append(f) 202 # wake event thread (message content is ignored) --> 203 self._event_pipe.send(b'') 204 else: 205 f() ~/Dev/notebook/jupyterenv/lib/python3.6/site-packages/zmq/sugar/socket.py in send(self, data, flags, copy, track, routing_id, group) 618 ) 619 data.group = group --> 620 return super().send(data, flags=flags, copy=copy, track=track) 621 622 def send_multipart( zmq/backend/cython/socket.pyx in zmq.backend.cython.socket.Socket.send() zmq/backend/cython/socket.pyx in zmq.backend.cython.socket.Socket.send() zmq/backend/cython/socket.pyx in zmq.backend.cython.socket._send_copy() ~/Dev/notebook/jupyterenv/lib/python3.6/site-packages/zmq/backend/cython/checkrc.pxd in zmq.backend.cython.checkrc._check_rc() KeyboardInterrupt:
When using while, one has to be sure that the condition can become false (can be falsified), else, it will generate an infinite loop.
You can use break to stop a loop before the condition is false (it's always better not to use it, but you might see it):
n = 0
while n < 9:
print(n)
if n == 7:
break
n = n + 1
0 1 2 3 4 5 6 7
Of course, for loops are easier to write in Python, so they are used more often than while. However, there are times when while loops will be easier to use:
available_ingredients = ["pepper", "leek", "mushroom", "carot"]
ingredient = input("Please enter an ingredient: ")
while ingredient not in available_ingredients:
print("I don't have that!")
ingredient = input("Please enter an ingredient: ")
print("Ah, yes,", ingredient, "I have some")
Please enter an ingredient: tomato I don't have that! Please enter an ingredient: brussel I don't have that! Please enter an ingredient: mushroom Ah, yes, mushroom I have some
🥳 Write a program that will:
import random
to_find = random.randint(0, 20)
print() for example)String methods: Check the W3School doc