閱讀《笨方法學python3》，歸納的知識點
相關代碼詳見github地址：https://github.com/BMDACMER/Learn-Python
習題1：安裝環境+練習 print函數使用 主要區別雙引號和單引號的區別
習題2：注釋符號#
習題3：運算符優先級，跟C/C++， Java類似
以下運算符優先級：從下往下以此遞增，同行為相同優先級
Lambda #運算優先級最低 邏輯運算符: or 邏輯運算符: and 邏輯運算符:not 成員測試: in, not in 同一性測試: is, is not 比較: <,<=,>,>=,!=,== 按位或: | 按位異或: ^ 按位與: & 移位: << ,>> 加法與減法: + ,- 乘法、除法與取余: *, / ,% 正負號: +x,-x
習題4：變量名+打印 介紹了以下這種形式的打印
print("There are", cars, "cars available.")
習題5：更多打印方式 比如 f"XXX"
my_name = 'Zed A. Shaw'
print(f"Let's talk about {my_name}")
習題6：繼續使用f"XX"打印
習題7：format打印方式，可采用end=‘ ’代替換行
print("Its fleece was white as {}.".format('show'))
print(end1 + end2 + end3 + end4 + end5 + end6, end=' ')
print(end7 + end8 +end9 + end10 +end11 + end12)
顯示如下：
Its fleece was white as show.
Cheese Burger
習題8：更多打印方式（這種打印方式見的較少）
formatter = '{} {} {} {}'
print(formatter.format(1, 2, 3, 4))
print(formatter.format("one", "two", "three", "four"))
print(formatter.format(True, False, False, True))
print(formatter.format(formatter, formatter, formatter, formatter))
# print("\n")
print(formatter.format(
"Try your",
"Own text here",
"Maybe a poem",
"Or a song about fear"
))
顯示如下：
1 2 3 4
one two three four
True False False True
{} {} {} {} {} {} {} {} {} {} {} {} {} {} {} {}
Try your Own text here Maybe a poem Or a song about fear
習題9：多行打印，換行打印
小結：打印方式
1）print("There are", cars, "cars available.") # 變量名直接打印
2）print(f"Let's talk about {my_name}") # 帶有f"{}"的打印方式
3） 變量名+format()
hilarious = False
joke_evaluation = "Isn't that joke so funny?! {}"
print(joke_evaluation.format(hilarious))
4）print("Its fleece was white as {}.".format('show')) #
5）formatter = '{} {} {} {}'
print(formatter.format(1, 2, 3, 4))
print(formatter.format("one", "two", "three", "four"))
6）print('''
There's something going on here.
With the three double-quotes.
We'll be able to type as much as we like.
Even 4 lines if we want,or 5,or 6
'''） # 多行打印
習題10：轉義字符
習題11：介紹 input()函數，並使用到習題5介紹的打印方式
print("How old are you?", end=' ')
age = input()
print("How tall are you?", end=' ')
height = input()
print("How much do you weight?", end=' ')
weight = input()
print(f"So,you're {age} old,{height} tall and {weight} heavy.")
習題12：介紹input()函數 加提示符
age = input("How old are you?")
print("How old are you? {}".format(input())) # 先運行后面的在運行前面的提示
習題13： 參數、解包和變量
from sys import argv
# read the WYSS section for how to run this
script, first, second, third = argv
print("The script is called:", script)
print("Your first variable is:", first)
print("Your second variable is:", second)
print("Your third variable is:", third)
# 注： 把argv中的東西取出，解包，將所有的參數依次復制給左邊的這些變量
>>python ex13.py first second third
練習14：提示與傳遞 主要講解 input()函數 配合輸入格式
from sys import argv
'''
PS E:\dev\code\笨方法學python3> python ex14.py Zed
Hi Zed,I'm the ex14.py script.'
I'd like to ask ypu a few questions.
Do ypu like me Zed?
>yes
Where do ypu live Zed?
>yicheng
What kind of computer do you have?
>Dell
'''
script , user_name = argv
prompt = '>'
print(f"Hi {user_name},I'm the {script} script.'")
print("I'd like to ask you a few questions.")
print(f"Do ypu like me {user_name}?")
likes = input(prompt)
print(f"Where do you live {user_name}?")
lives = input(prompt)
print("What kind of computer do you have?")
computer = input(prompt)
print(f'''
Alright, so you said {likes} about liking me.
You live in {lives}. Not sure where that is.
And you have a {computer} computer. Nice.
''')
練習15：讀取文件
txt = open(filename)
print(f"Here's your file {filename}:")
print(txt.read())
txt.close()
練習16：讀寫文件
close:關閉文件。跟你的編輯器中的“文件”->“保存”是一個意思
read：讀取文件的內容
readline：只讀取文本文件中的一行
truncate：清空文件，請小心使用該命令
write('stuff')：將“stuff”寫入文件
seek（0）： 將讀寫位置移動到文件開頭
練習17：繼續讀寫文件
in_file = open(from_file) indata = in_file.read() out_file = open(to_file,'w') out_file.write(indata)
練習18：函數
練習19：函數與變量
pytyon在定義函數的時候跟C/C++區別蠻大，python不需要定義參數類型，定義某一函數時 可參考如下：
def function(vailable1, vailable2,*):
練習20： 函數和文件
from sys import argv
script, input_file = argv
def print_all(f):
print(f.read())
def rewind(f):
f.seek(0)
# 帶有行號的打印內容
def print_a_line(line_count,f):
print(line_count, f.readline())
current_file = open(input_file) # 接受的參數，打開文件
print("First let's print the whole file:\n")
print_all(current_file) # 打印該文件
print("Now let's rewind, kind of like a tape.")
rewind(current_file) # 將讀寫位置移動到文件開頭（第一個字符的前面一個位置） 方便后續讀取 如不執行該操作，后續打印為空
print("Let's print three lines:")
current_line = 1
print_a_line(current_line,current_file)
current_line = current_line + 1
print_a_line(current_line,current_file)
current_line = current_line + 1
print_a_line(current_line, current_file)