# Python 101
體驗半隻腳踏入 cs 世界的日常
**01 Intro**
https://hackmd.io/@lhsueh1/python101_intro
:::spoiler **02 Accumulation**
**Boolean**
| | | and | or|
| -------- | -------- | -------- |---|
|1|0|False|True
|1|1|True|True
|0|0|False|False
|0|1|False|True
**range**
```range(開頭, 結尾, 間隔)```
**conditional**
```python
if (a):
print("a is True!")
elif(b):
print("b is True")
else:
print("no one is True")
```
**for loop**
```python
for i in range(10):
print(i) # i-> 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
```
**while loop**
```python
while(run_below_if_true):
print("forever")
if(condition):
break #ends while loop
```
**random**
``` python
import random
random.randrange(10) #random number between 0-9
```
:::
https://hackmd.io/@lhsueh1/python101_Accumulation
:::spoiler **03 Function**
**function**
``` python
def sum_of_square(a, b):
ans = ((a + b)**2) - (2*ab)
return ans
def main(): #main function, good practice
a = sum_of_square(2, 5)
print(a) #will print 29
main()
```
:::
https://hackmd.io/@lhsueh1/python101_Function
:::spoiler **04 Immutable Data Types**
**string**
``` python
myString = "Hello World"
len(myString) #get length
# strings are indexable!
print(myString[0]) #prints 'H'
```
**tuple**
``` python
a = (13, 5)
# tuples are indexable!
```
:::
https://hackmd.io/@lhsueh1/HyxB7ac8j
Indirect proof & 3n + 1
https://hackmd.io/@lhsueh1/rkfthUxwj
:::spoiler **05 List**
**List**
``` python
mylist = [1, 2, 3, 4]
# lists are indexable!
print(mylist[0]) #print first element
len(mylist) #get length
mylist.append(4) # add 4 to the end of the list
mylist.pop() # remove the last element of the list
```
:::
https://hackmd.io/@lhsueh1/BJ7Z3VFvj
Recursion
https://hackmd.io/@lhsueh1/HyUdJhtvj
Turtle
https://hackmd.io/@lhsueh1/S1zzzYzds
:::spoiler **06 Dictionary**
``` python
mydict = {"twelve":12, "six":6, "twenty":20}
#前者 key 後者 value
print(mydict["six"]) #access through key, will print 6
print(mydict.get("sixx")) #safe way to access through key
mydict["one"] = 1 #新增
for i, j in mydict.items(): #access with loop
print(j, i) #i: key, j: value
```
:::
https://hackmd.io/@lhsueh1/SyctFNRts
:::spoiler **07 File I/O & module**
- write
``` python
file = open("test.txt", "w")
file.write("hi")
file.close()
```
- append
``` python
file = open("test.txt", "a")
file.write("hi_2")
file.close()
```
- for loop 讀法 (一次拿一行
``` python
fref = open("test.txt", "r")
for line in fref:
print(line)
fref.close()
```
- readline() 讀法 （一次一行
``` python
fref = open("test.txt", "r")
print(fref.readline())
print(fref.readline())
print(fref.readline())
fref.close()
```
- readlines() 讀法（一次全部
``` python
fref = open("test.txt", "r")
print(fref.readlines())
fref.close()
```
- read() 讀法（一次全部
``` python
fref = open("test.txt", "r")
print (fref.read())
fref.close()
```
:::
https://hackmd.io/@lhsueh1/HJ5YFECKs
JSON <3
https://hackmd.io/@lhsueh1/BygVYReno
:::spoiler **08 Class**
``` python
class Rectangle:
def __init__(self):
self.width = 10
self.height = 10
self.color = "red"
def get_area(lines="The area is... "):
return lines + str(self.width * self.height)
r = Rectangle()
r.width = 20
print(r.get_area()) # The area is... 200
r.height = 1
print(r.get_area("->>")) # ->>20
```
:::
https://hackmd.io/@lhsueh1/B17iF0ghi
**Pygame**
https://hackmd.io/@lhsueh1/BJM6ITBTs
`What's next`
https://hackmd.io/@lhsueh1/r1mRinrni
<br></br>
---
:::spoiler Not included
- Exceptions
- Network
- Inheritance
- Testing
- Git
- Basic Linux
- ...
:::
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