Python Crash Course 7 - Input and While

I’m YouKoutaku. These codes are from the book python_Crash_Course, 2nd edition. I learned python and took these notes for this book.

7.Input and While

7.1 input()

input(prompt)

message = input("Tell me something, and I will repeat it back to you:")
print(message)

Yes

7.1.1

name = input("Please enter your name:")
print(f"\n Hello,{name}!")

 Hello,Yang Guangze!

prompt = "If you tell us who you are, we can personalize the messages you see."
prompt += "\n What is your first name?"
name = input(prompt)
print(f"\nHello,{name}!")

Hello,Eric!

### input() to get int number
age = input("How old are you?")
print(type(age))
age = int(age)
print(type(age))

<class 'str'>
<class 'int'>

# %= reminder
4%3

1

7.2 while loop

7.2.1 sample

num = 1
while num <= 5:
    print(num)
    num +=1

1
2
3
4
5

7.2.2 exit loop

prompt = "\nTell me something, and I will repeat it back to you:"
prompt += "\nEnter 'quit' to end the program."
message = ""
while message != 'quit':
    message = input(prompt)
    print(message)

Y
Yang
Hello
quit

prompt = "\nTell me something, and I will repeat it back to you:"
prompt += "\nEnter 'quit' to end the program."
while message != 'quit':
    message = input(prompt)
    if message != 'quit':
        print(message)

Y
Yang
Hello

7.2.3 use flag in while

prompt = "\nTell me something, and I will repeat it back to you:"
prompt += "\nEnter 'quit' to end the program."

active = True
while active:
    message = input(prompt)
    if message == 'quit':
        active = False
    else:
        print(message)

Hello
can 
you
here
me
Ok

7.2.4 break in loop

prompt = "\nTell me something, and I will repeat it back to you:"
prompt += "\nEnter 'quit' to end the program."

while True:
    message = input(prompt)
    if message == 'quit':
        break
    else:
        print(message)

H
e
l
l
o

7.2.5 continue in loop

num = 0
while num < 10:
    num += 1
    if num % 2 == 0:
        continue
    print(num)

1
3
5
7
9

7.2.6 avoid infinity loop

x = 1
while x < 5:
    print(x)

1
1
1
1
1
.
.
.
---------------------------------------------------------------------------

KeyboardInterrupt                         Traceback (most recent call last)

Input In [22], in <cell line: 2>()
      1 x = 1
      2 while x < 5:
----> 3     print(x)


File c:\Users\ygz19\AppData\Local\Programs\Python\Python310\lib\site-packages\ipykernel\iostream.py:528, in OutStream.write(self, string)
    518 def write(self, string: str) -> Optional[int]:  # type:ignore[override]
    519     """Write to current stream after encoding if necessary
    520 
    521     Returns
   (...)
    525 
    526     """
--> 528     if not isinstance(string, str):
    529         raise TypeError(f"write() argument must be str, not {type(string)}")
    531     if self.echo is not None:


KeyboardInterrupt: 

7.3 using while to process list and dictionary

7.3.1 move the element in list

#stack: first in,last out
unconfirmed_users = ['alice','brian','candace']
confirmed_users = []

while unconfirmed_users:
    current_user = unconfirmed_users.pop()
    print(f"Verifying user: {current_user.title()}")
    confirmed_users.append(current_user)

print("\nThe following users hav been confirmed:")
for confirmed_user in confirmed_users:
    print(confirmed_user.title())

Verifying user: Candace
Verifying user: Brian
Verifying user: Alice

The following users hav been confirmed:
Candace
Brian
Alice

7.3.2 deletee all of the elements in list

pets = ['dog','cat','dog','goldfish','cat','rabbit','cat']
print(pets)

while 'cat' in pets:
    pets.remove('cat')

print(pets)

['dog', 'cat', 'dog', 'goldfish', 'cat', 'rabbit', 'cat']
['dog', 'dog', 'goldfish', 'rabbit']

7.3.3 using input to add dictionary

rs = {}
active = True
while active:
    name = input("\nWhat is your name?")
    r = input("Which mountain would you like to climb someday?")
    
    rs[name] = r
    
    repeat = input("Would you like to let another person respond?(y/n)")
    if repeat == 'n':
        active = False
print("\n-- Poll Results ---")

for name, r in rs.items():
    print(f"{name} would like to climb {r}.")

-- Poll Results ---
Y would like to climb L.
yang would like to climb l.