Input Loops¶
⚙️ Types¶
1 + 1
2
'1' + '1'
'11'
type(1)
int
type(True)
bool
type('1')
str
When you put quotes around text, that text becomes a string (str).
Strings are sequences of graphical symbols.
2 is the numeric integer "two".
'2' is the graphical symbol "2".
🎨 Basic Operators¶
10 + 7
17
When used with ints, + adds them together.
'fire' + 'place'
'fireplace'
When used with strs, + concatenates them together.
7 - 3
4
- does subtraction.
'nickname' - 'name'
--------------------------------------------------------------------------- TypeError Traceback (most recent call last) Cell In[10], line 1 ----> 1 'nickname' - 'name' TypeError: unsupported operand type(s) for -: 'str' and 'str'
Python doesn't let you subtract strings (only "add" them).
"water bottle" - "banana"
--------------------------------------------------------------------------- TypeError Traceback (most recent call last) Cell In[11], line 1 ----> 1 "water bottle" - "banana" TypeError: unsupported operand type(s) for -: 'str' and 'str'
🎨 Comparisons¶
8 == 9
False
9 == 9
True
"cat" == "dog"
False
"cat" == "cat"
True
You use == (two equals signs) to see if two things are equal.
You use = (one equals sign) to give a variable a value.
number = 9
if number == 8:
print('The number is 8')
else:
print('The number is not 8')
The number is not 8
8 > 7
True
3 < 8
True
"aardvark" < "zebra"
True
"cassowary" > "banana boat"
True
'mango' < 'muffin'
True
'cat' < 'catastrophe'
True
'Zebra' < 'aardvark'
True
Using > or < on strings tells you which string comes before the other alphabetically.
The "aphabetical order" of strings is defined by the ASCII table:
...0123456789...ABCDEFG...abcdefg...
"banana" > "🫢"
False
🖌 Input Loops¶
road_trip.py¶
break means break out of the current loop.
It doesn't matter whether the condition is True or False, break will stop the loop.
The next line of code to run is whatever follows the while loop.
NOTE
Yes:
response == "yes" or response == "Yes"
No:
response == "yes" or "Yes"
int¶
"123" > "23"
False
123 > 23
True
bigger.py¶
input always returns a string.
You can use int() to turn a string into an integer.
Key Ideas¶
- types
intvsstr
+,-+also works on strings
==,<,>- work with both integers and strings
- Input loops
breakorreturnto get out of a loop