py项目中学到的知识梳理

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两个月前需求:使用python3做一个将观测数据编译产出成bufr数据的一个工具
刚刚完成初版,其中的数据文件路径和数据内容格式还需要仔细核对,但整体逻辑已实现,剩下的工作时间可能会用来完善它

Anaconda3

The open-source Anaconda Distribution is the easiest way to perform Python/R data science and machine learning on Linux, Windows, and Mac OS X. With over 11 million users worldwide, it is the industry standard for developing, testing, and training on a single machine, enabling individual data scientists to:

python 读取 XML

from xml.dom import minidom


def readXmlByTagName(path):
    with open(path, 'r', encoding='utf8') as fh:
        # 获取根节点
        root = minidom.parse(fh).documentElement
        # 节点类型:'ELEMENT_NODE',元素节点; 'TEXT_NODE',文本节点; 'ATTRIBUTE_NODE',属性节点
        #print('节点类型:')
        return root
def getElementsByTagName(root,tagName):
    return root.getElementsByTagName(tagName)[0].childNodes[0].data

DataFrame --- pandas

pandas is an open source, BSD-licensed library providing high-performance, easy-to-use data structures and data analysis tools for the Python programming language.
pandas 的使用效果很腻害,在项目中主要用来读取如下图格式数据:
image.png

用到的 pandas 语法大概有:

  • pandas.read_table(data_path, sep=',',dtype = 'str') 用来将数据读取出来
  • .shape[0] 用来获取数据的行数
  • .iloc 根据 x 和 y 轴来定位元素
  • 文档地址

十进制转二进制

def Number2BinStr(num, size):

	'''
	整形转二进制字符的方法;
	:param num: 需要变换的整数;
	:param size:设定二进制宽度
	:return:
	'''
	fmt = '{0:0%db}' % size
	return fmt.format(num),size

字符串转二进制

def encode(s='', size=8):
   str_len = len(s)
   if str_len*8 <size:
      for i in range(0, int((size - str_len*8)/8)):
         s = s + ' '
   elif str_len*8 >size:
      pass
      # s = s
      # for i in range(0, int((str_len*8 - size)/8)):
   strs = ''
   for c in s:
      str_byte = bin(ord(c)).replace('0b', '')
      b = 8 - len(str_byte)
      for i in range(0, b):
         str_byte = '0'+str_byte
      strs = strs + str_byte
   return strs, size

求数据乘以比例因子加系数

def data_trasform_func(data, x, b):
   '''
   求数据乘以比例因子加系数的方法;
   :param data: 数据值;
   :param x:比例因子
   :param b:基准值
   :return:返回转换后的值;
   '''
   return int(data*math.pow(10, x) + b)

判断某文件夹下是否包含某个名称的文件,仅支持单个词模糊查询

#判断是否有数据文件
def search(path=".", name=""):
    result = []
    for item in os.listdir(path):
        item_path = os.path.join(path, item)
        if os.path.isdir(item_path):
            search(item_path, name)
        elif os.path.isfile(item_path):
            if name in item:
                result.append(item_path)
    return result

bufr 编码格式附件

bufr 编码格式规则.rar

判断对象是不是空

if (type(None) != type(aapae33) and type(None) != type(aapae33object))

获取前一天时间

#UTC时间获取前一天

td = datetime.timedelta(days=1,hours=0,,seconds=0,microseconds=0)
print(datetime.datetime.utcnow().isoformat())
print((datetime.datetime.utcnow() - td).isoformat())

#本地时间获取前一天
now_time = datetime.datetime.now()
yes_time = now_time + datetime.timedelta(days=-1)
print(now_time)
print(yes_time)

获取文件指定行内容

import linecache
file_path = r'D:\work\python\test.txt'
line_number = 5
context = linecache.getline(file_path, line_number).strip()

标题:py项目中学到的知识梳理
作者:cuijianzhe
地址:https://solo.cjzshilong.cn/articles/2019/06/14/1560505233857.html