# myPythonNotebook [good online book for beginners](https://greenteapress.com/wp/think-python-2e/) # Learning steps setup - python, vscode, git, pip basic cmd use - python -v - vscode python core concepts - output - data types - input - type casting - int(input()) - operators - if else - loop - list, string - while loop - for loop - module, import - math module - // next level - mutable, immutable - set, dict, tuple - function - recursion syntax - indentation - keep spaces between comma problems to do https://onlinejudge.u-aizu.ac.jp/courses/lesson/2/ITP1/1 # array create 2D array ```python rn, cn = (3, 5) arr = [[0 for _ in range(cn)] for _ in range(rn)] arr2 = [[0] * cn] * rn arr3 = [] for _ in range(rn): temp = [] for _ in range(cn): temp.append(0) arr3.append(temp) ``` # tuple You cannot remove elements from the tuple https://www.w3schools.com/python/python_tuples_unpack.asp # set list cant be an elem of set, but tuple can ```python! #create an empty set set1 = set() bandNameSet = {"The Cabs", "3nd"} set1.add(int(input())) x = int(input()) #2 ways to remove elements, only use .remove(x) when x is definitely in the set, otherwise use .discard(x) if x in set1: set1.remove(x) set1.discard(x) #joining other sets to set3 set3.update(set1, set2) #iterate through the set for idx, x in enumerate(set): print("index ": idx + ", set_value: " + x) ``` list and set are interchangable by list(mySet) or set(myList) # dictionary ```python= studentIdList = { "Peter":3012345670, "Jaylen":3022345670} #search if x is one of the key in the dict if x in myList: print("yes") #get value myDict.get(key) #get key #O(n) iterate the container #add new key-value pair myDict.update({key:value}) #remove a key-value pair del myDict[key] #loop through key for x in myMap: ... #loop through key, value for thisKey, thisValue in myMap: ... ``` # string ## fstring ```python= a = int(input()) b = int(input()) c = a**b print(f'{a} ** {b} is {c}') ``` ## rstring ignore special character (i.e. \n \r \a) # string functions ## s.find() ## s.replace() # map(function, para1, para2, ...) create an object with outputs from the function with the given parameters # filter only 1 parameter (a list) create an object with inputs verfied by the function ```python= #dont output this filter(func1, para) #have to make it into a list first list(filter(func1, para)) ``` # lambda function lambda para1, para2, ... : (content)