Python语法

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列表

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def get_factors2(number):
  import math
  factors = []
  sqrt = math.sqrt(number)
  # print(f"{number}的开方数{sqrt:.3f}")
  for i in range(1, int(sqrt)+1):
    if number % i == 0:
      factors.append(i)
      if number // i != i:
        factors.append(number // i)
  # print(factors)
  return sorted(factors)

if __name__ == '__main__':
  i = 0
  factors = get_factors2(100)
  print(factors)
  for f in factors:
    print(f"factors[{i}]: {factors[i]}")
    i += 1

字典

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#!/bin/env python3
import os
book_list = [
    {'name':"数学1年级上册", 'url':"https://v3.ykt.cbern.com.cn/65/document/40a22857f0234ab1b1827998d588d927/pdf.pdf"},
    {'name':"数学1年级下册", 'url':"https://v3.ykt.cbern.com.cn/65/document/39c42025a2d848bf8c57ff612439ceb3/pdf.pdf"},
    {'name':"数学2年级上册", 'url':"https://v2.ykt.cbern.com.cn/65/document/6490bb97b5ad41fb83e2b3dbd28b8fe0/pdf.pdf"},
    {'name':"数学2年级下册", 'url':"https://v2.ykt.cbern.com.cn/65/document/2a3ceb3318714414ad0d658af901ea77/pdf.pdf"},
    {'name':"数学3年级上册", 'url':"https://v2.ykt.cbern.com.cn/65/document/32c6b18bca334b439ba061ac958d9d3f/pdf.pdf"},
    {'name':"数学3年级下册", 'url':"https://v3.ykt.cbern.com.cn/65/document/01c4d03170af48d1b88ea5efdfcb5011/pdf.pdf"},
    {'name':"数学4年级上册", 'url':"https://v1.ykt.cbern.com.cn/65/document/f86d42fd514c4945b27a4166e3deb8a3/pdf.pdf"},
    {'name':"数学4年级下册", 'url':"https://v1.ykt.cbern.com.cn/65/document/d0a86fb3780b4a1f92db6025aa5683bd/pdf.pdf"},
    {'name':"数学5年级上册", 'url':"https://v1.ykt.cbern.com.cn/65/document/c07eb72ef5044b339bde311968ad3e31/pdf.pdf"},
    {'name':"数学5年级下册", 'url':"https://v1.ykt.cbern.com.cn/65/document/00149c6d79044fa08e7d03f78cdb4145/pdf.pdf"},
    {'name':"数学6年级上册", 'url':"https://v1.ykt.cbern.com.cn/65/document/b1950c9c9dcc43919f60824c1b258b06/pdf.pdf"},
    {'name':"数学6年级下册", 'url':"https://v2.ykt.cbern.com.cn/65/document/9547d96598ec4966876698c225bcfd11/pdf.pdf"}
]

for book in book_list:
    # print(book['name'], book['url'])
    command = f"wget {book['url']} -O {book['name']}.pdf"
    print(command)
    os.system(command)

字符串

f””

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h = "hello"
w = "world"
f"{h} {w}"
输出：hello world

format函数

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# 不带位置转换
"{} {}".format("hello", "world")
输出：hello world

# 带位置转换
"{0} {1}".format("hello", "world")
输出：hello world

"{1} {0} {1}".format("hello", "world")
输出：world hello world

字典

遍历

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# 使用items()方法遍历字典
my_dict = {'name': 'Tom', 'age': 18, 'sex': '男'}
for key, value in my_dict.items():
    print(key, value)
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my_dict = {'name': 'Tom', 'age': 18, 'sex': '男'}
for key in my_dict:
    print(key, ':', my_dict[key])

lambda匿名函数

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f = lambda x: x*x
print(f(5))
print((lambda y: y*y)(10))

DataFrame

创建DataFrame对象

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import pandas as pd
import numpy as np
df = pd.DataFrame(np.random.random((3, 5)))
df.columns = ['a', 'b', 'c', 'd', 'e']
print(df)

运行结果：

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          a         b         c         d         e
0  0.493908  0.129874  0.715260  0.725369  0.994077
1  0.021717  0.369733  0.070762  0.940723  0.637749
2  0.201970  0.075588  0.103985  0.706798  0.635883

访问DF对象的列

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print(df.columns)
print(df.columns.tolist())

运行结果：

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Index(['a', 'b', 'c', 'd', 'e'], dtype='object')
['a', 'b', 'c', 'd', 'e']

访问DF对象的索引

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print(df.index)

运行结果：

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RangeIndex(start=0, stop=3, step=1)

删除行

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df = df.drop(index=[0, 1, 2]) # 删除第0-2行
print(df)

运行结果：

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Empty DataFrame
Columns: [a, b, c, d, e]
Index: []

创建空对象

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df2 = pd.DataFrame(data=None, columns=['Name', 'Birthday', 'Address'])
print("df2:", df2)

运行结果：

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df2: Empty DataFrame
Columns: [Name, Birthday, Address]
Index: []

打印完整数据

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# display.max_rows的默认值是10
# display.max_columns的默认值是10
klines = self.api.get_kline_serial(self.symbols, 60, data_length=5)
with pd.option_context('display.max_rows', None, 
                       'display.max_columns', None,
                       'display.width', None,
                       'display.max_colwidth', None
                       ):
    print(klines)

方式二、

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# Permanently changes the pandas settings
pd.set_option('display.max_rows', None)
pd.set_option('display.max_columns', None)
pd.set_option('display.width', None)
pd.set_option('display.max_colwidth', None)

klines = self.api.get_kline_serial(self.symbols, 60, data_length=5)
print(klines)

运行结果：

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       datetime       id    open    high     low   close  volume  open_oi  close_oi     symbol  duration
0  1.687141e+18  62033.0  2182.5  2183.0  2181.5  2182.5    51.0  47595.0   47585.0  DCE.j2309        60
1  1.687141e+18  62034.0  2182.5  2182.5  2180.0  2181.0    67.0  47585.0   47614.0  DCE.j2309        60
2  1.687141e+18  62035.0  2181.0  2181.0  2178.0  2178.0   165.0  47614.0   47622.0  DCE.j2309        60
3  1.687141e+18  62036.0  2178.0  2180.0  2177.5  2180.0   104.0  47622.0   47580.0  DCE.j2309        60
4  1.687141e+18  62037.0  2180.0  2182.0  2180.0  2182.0    80.0  47580.0   47581.0  DCE.j2309        60