Python 数据分析：

1. python 语言精要
2. Ipython
3. numpy
4. pandas
5. 数据加载
6. 数据处理
7. 数据绘图可视化

chapter 1 python语言精要

重点了解类型 ，和不同数据结构

1. if you want to run the document of the python

$ python hello_world.py

if you run the the code in the python interpreter “Ipython”
you can enter

%run hello_word.py

the difference between the python and other programming language

a = [1,2,3]
b = a
a.append(4)
In[ ] ：b
[1,2,3,4]

the situation is similar with the pointer of the language C

type
Var is the name of the objective, the info of the type is reserved in the interior of the objectives
use the function isinstance (var,(type,type2,…)) to confirm the type .
type list :str int float bool,the int can be translate to the long int automatically

introduce the functions from the module

example:
there is a module"TEST", we can find the defined var PI,the function f(x) , g(a,b)
way 1

import  TEST
result = TEST.f(6)
a=TEST.PI

way 2

from TEST  import f,g,PI
a=g(4,PI)

simplify the name

import TEST as ts
from TEST import PI as a ,g as gf
r1 = ts.f(a)
r2=gf(6,a)

no use the from module_name import module_var/module_function
we should call function use module_name.module_function

dictionary

# 1、create the new dictionary
my_dict = { key1 : value1, key2 : value2, key3 :value3}
# 2、add new key4 & value4
my_dict[key4] = value4
# 3、drop the key3 ,value3
del my_dict[key3]
or  my_new_dict = my_dict.pop( key3 )
# 4、dispaly the list of keys or values
my_dict.keys()
my_dict values()
# 5、combine the two dictionary
my_dict.update({key5 : value5 , key6 :value6})  {} can replaced by the name of the dict
#  6、from sequence to the dictionary
new_dict =dict(zip(sequence1,sequence2))

words =['apple','bat','bar','atom','book']
by_letter ={}
for word in words:
letter=word[0]
if letter not in by_letter:
by_letter[letter]=[word]
else:
by_letter[letter].append(word)

if-else :by_letter.setdefault(letter,[]).append(word)

date structure

tuple 拆包 内在value赋值