Basic Element and Grammer of Coding

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前言

you must begin at this page: 3. An Informal Introduction to Python — Python 3.5.4rc1 documentation

python is a language, like nature language, built by basic elements. English is built by letters, Python is built by letters, numbers and symbols.

type letter number symbol
Function replace/refer to calculation/index 处理
e.g. variy/def +/[] 1/1/[-1]

mix them to be a word, then to be sentence, and then a paragraph. a single line of code can translate to a pargraph of natule language.

数字和符号放一起, 是计算

e.g. 

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1 + 1 #addition
2

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2 ** 7 #square
128

字母词 = 数字 是变量

e.g.1

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girl = 10
boy = 20
girl + boy
30

e.g.2
变量赋值任何数字后, 之后继续使用这个变量.

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line_n = 0 
limit > 10000
lm = Counter() 
line_n += 1

引号里面有文字, 整个是字符串

e.g.

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l = 'hello world'
print (s)
hello world

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n = '1'
print (n)
1

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s = '*'
print (s)
*

string is like word, same as number , it can be deal with.

‘字母词 后面跟的[ ]表示位置索引 : - ‘ ‘number’

e.g.

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w = 'python'
w[0] #the first letter of 'python'
'p'

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w[:2]#the first letter to the second letters of 'python'
'py'

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w[-1]# the last letter of 'python'
'n'

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w[:-2]# the first letter to the last two letters of 'python'
'pyth'

‘字母词做容器( list/counter/dict)时 后面跟的[ ]表示其中的元素( elements)

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lm = Counter()
lm[key]

The built-in function len() returns the length of a string:

e.g.

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s = 'ninwoebnihgiyi'
len(s)
14

s = [ , ] is list

e.g.

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s = [1,2,3,4]
s
[1, 2, 3, 4]

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s[0]
1

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s[2]
3

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s[2:5]
[3, 4]

begin programing

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a, b =0, 1
while b < 1000:
    print (b, end = ',')
    a, b = b, a+b
1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,

print ()

  • writes the value of the argument(s) it is given.
  • multiple arguments, floating point quantities, strings
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i = 256*256
print('the value of i is', i)
the value of i is 65536

xx.xx() is module.function for (content)

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