Alright, let's do it
오늘만 외부 강의를 통해 배우도록 하자!(maybe?)
Python D-1 (Starts with Hello World)
Step 1. print (...)
print -> This is display all the texts written inside of (.....)
Remember - Don't forget to use -> ""
I also must consider the types of text or number
1. int(integer) - ex. 1, 2, 3, 4....
2. float - ex. 3.14, 5.16
예를 들어,
x = 10 -> For this, x는 상자라고 치고 이름만 x라고 정의한 것, 그 안에는 타입에 알맞은 것을 넣으면 된다
여기서또 다른 포인트, 정수인지, 텍스트인지, 아니면 또 다른 데이터인지 확인 한 후 만들자.
x라는 상자를 만든다 한들, x = hello world라고 하니 에러가 떴다. 즉, 알맞게 사용해야겠다.
확실히 따로 상자를 만들어 그 안에 넣다보니 나중에 사용할 때 용이했다.
print (10-5)보다
x = 10
y = 5
print (x-y) - much better
tips! -> remember
* -> Multiply
/ -> division
// -> division but in float type
% -> It only gets the remain
** -> Exponent
or
I could see that there are multiple things that I must remember. not like X x Y but X*Y
divmod() -> shows the answer of both / and %
print (divmod(x ,y))
문자열을 쓸 때에는 상자를 만들고 상자 안에 넣을 문자를 넣기위해 ""을 쓴다 -> Don't forget
Things that are needed when using string
escape
\\ -> \
ex -> print ("hello\\world") -> hello\world
\n -> line break
ex -> print ("hello\nworld") -> hello
world
\b -> backspace
ex -> print ("hello\bworld") -> hellworld - hello -> hell
\t -> tap
ex -> print ("hello\tworld") -> hello world
\' or \" -> just ' or "
ex -> print("hello\"world) -> hello"world
but isn't it the same as " ' "?
ex->
print ("hello'world'") -> hello'world'
realized that I could not add another ""
print ("hello"world"") -> error
print ("hello\"world\"") -> correct -> hello"world"
x = "hello"
y = "world"
print (x + y) -> helloworld
print (x*3 + y*2) -hellohellohelloworldworld
len -> shows the length of the text
print(len(x)) -> 5
indexing and slicing -> probably using []
ex-> print (x[0]) -> h ('h'ello) -> means 'please take the 0th text'
remember!!!!!!! -> It always starts with 0.
h - 0
e - 1
l - 2
l - 3
o - 4
print (x[:2]) -> he -> means 'please takes only 2 texts'
.replace -> replacing the texts
ex -> print (x.replace("hello", "hi")) -> means print x but change it to 'hi' from 'hello' ("hello" -> "hi")
text formatting (%s, %(...))
tips
%s- string
%d- int
%f- float
ex.
x = "Kevin"
I must be awarded the types. %s, %d, %f
print ("Hello, my name is %s." %x) -> Hello, my name is Kevin
y = 3
print("I'm %d years old" %y) -> %d = text type, %y = choosing y to insert number or text to %d
ex.
a = "Nice to "
b = "meet you"
c = "Jenny"
d = 24
print ("%s%s, my name is %s and I'm %d years old." %(a, b, c ,d))
-> must make sure it follows in order
-> Nice to meet you, my name is Jenny and I'm 24 years old
format
print ("{0}{1}, my name is {2} and I'm {3} years old.".format(a, b, c, d))
-> Nice to meet you, my name is Jenny and I'm 24 years old
It's like the %s thing but it seems that it is much more convenient to recognize the order.
f- string
print (f"{a}{b}, my name is {c}" )
-> Nice to meet you, my name is Jenny
-> I need to put the a, b, c into wherever I want -> pretty easy
float f{num: rounding)
f = 64.123456789
print (f{f:0.4f) (will be rounded at 5th num) (remember to put f(0.4f))
-> 64.1235
finding or counting the texts
counting(.count("text you want to count")
x = "aaaabbbccccddd"
print (x.count("a"))
-> 4 = means there are four a in the sentence
finding(.find("text you want to find"))
print (x.find("c"))
-> 7 = means the first spell c is at the 7th in the sentence (remember it always starts with 0)
It will show -1 if I search for a number or text that doesn't exist in the sentence
.index = same as .find but it will not return -1 but gives you an error
.join()
print("/".join(x)) -> a/a/a/a/b/b/b/c/c/c/c/d/d/d
It will insert / every side of the texts
Upper or lower spelling
print (x.upper()) -> AAAABBBCCCCDDD
print (x.lower()) -> aaaabbbccccddd
removing blank (.rstrip(), .lstrip(), strip())-> seems it removes all the blanks in the sentence
x = " A "
print(x.rstrip()) -> A
print(x.lstrip()) ->A
print(x.strip()) ->A
split (.split(symbol to split between the texts)
it can be .split() - blank, but if there is a certain symbol, you must add ""
x = "A : B"
print (x.split(" : "))
Done for today 'V'b
Things that I must remember today
1. How to write and use the factors. (.split, .rstrip etc.)
2. Must know the types of the text.