政务服务平台开发需要注意如何提升小程序跨平台兼容性与用户体验
692
2022-09-22
DataAnalysis-读取本地数据
一、TXT文件操作
读取全部内容
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import numpy as np
import pandas as pd
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txt_filename = './files/python_wiki.txt'
# 打开文件
file_obj = open(txt_filename,'r')
# 读取整个文件内容
all_content = file_obj.read()
# 关闭文件
file_obj.close()
print (all_content)
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Python is a widely used high-level, general-purpose, interpreted, dynamic programming language.[24][25] Its design philosophy emphasizes code readability, and its syntax allows programmers to express concepts in fewer lines of code than possible in languages such as C++ or Java.[26][27] The language provides constructs intended to enable writing clear programs on both a small and large scale.[28]
Python supports multiple programming paradigms, including object-oriented, imperative and functional programming or procedural styles. It features a dynamic type system and automatic memory management and has a large and comprehensive standard library.[29]
Python interpreters are available for many operating systems, allowing Python code to run on a wide variety of systems. CPython, the reference implementation of Python, is open source software[30] and has a community-based development model, as do nearly all of its variant implementations. CPython is managed by the non-profit Python Software Foundation.
逐行读取
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txt_filename = './files/python_wiki.txt'
# 打开文件
file_obj = open(txt_filename, 'r')
# 逐行读取
line1 = file_obj.readline()
print (line1)
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Python is a widely used high-level, general-purpose, interpreted, dynamic programming language.[24][25] Its design philosophy emphasizes code readability, and its syntax allows programmers to express concepts in fewer lines of code than possible in languages such as C++ or Java.[26][27] The language provides constructs intended to enable writing clear programs on both a small and large scale.[28]
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# 继续读下一行【不会全部读完】
line2 = file_obj.readline()
print (line2)
# 关闭文件
file_obj.close()
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Python supports multiple programming paradigms, including object-oriented, imperative and functional programming or procedural styles. It features a dynamic type system and automatic memory management and has a large and comprehensive standard library.[29]
读取全部内容,返回列表
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txt_filename = './files/python_wiki.txt'
# 打开文件
file_obj = open(txt_filename, 'r')
lines = file_obj.readlines()
for i, line in enumerate(lines):
print ('%i: %s' %(i, line))
# 关闭文件
file_obj.close()
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0: Python is a widely used high-level, general-purpose, interpreted, dynamic programming language.[24][25] Its design philosophy emphasizes code readability, and its syntax allows programmers to express concepts in fewer lines of code than possible in languages such as C++ or Java.[26][27] The language provides constructs intended to enable writing clear programs on both a small and large scale.[28]
1: Python supports multiple programming paradigms, including object-oriented, imperative and functional programming or procedural styles. It features a dynamic type system and automatic memory management and has a large and comprehensive standard library.[29]
2: Python interpreters are available for many operating systems, allowing Python code to run on a wide variety of systems. CPython, the reference implementation of Python, is open source software[30] and has a community-based development model, as do nearly all of its variant implementations. CPython is managed by the non-profit Python Software Foundation.
写操作
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txt_filename = './files/test_write.txt'
# 打开文件
file_obj = open(txt_filename, 'w')
# 写入全部内容
file_obj.write("《Python数据分析》")
file_obj.close()
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txt_filename = './files/test_write.txt'
# 打开文件
file_obj = open(txt_filename, 'w')
# 写入字符串列表
lines = ['这是第%i行\n' %n for n in range(10)]
file_obj.writelines(lines)
file_obj.close()
with语句
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txt_filename = './files/test_write.txt'
with open(txt_filename, 'r') as f_obj:
print (f_obj.read())
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这是第0行
这是第1行
这是第2行
这是第3行
这是第4行
这是第5行
这是第6行
这是第7行
这是第8行
这是第9行
二、CSV文件操作
pandas读csv文件
根据路径导入数据以及指定的列
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import pandas as pd
filename = './files/presidential_polls.csv'
df = pd.read_csv(filename, usecols=['cycle', 'type', 'startdate'])#导入指定列
print (type(df))
print (df.head())
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cycle type startdate
0 2016 polls-plus 10/25/2016
1 2016 polls-plus 10/27/2016
2 2016 polls-plus 10/27/2016
3 2016 polls-plus 10/20/2016
4 2016 polls-plus 10/20/2016
引用指定的列
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cycle_se = df['cycle']
print (type(cycle_se))
print (cycle_se.head())
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0 2016
1 2016
2 2016
3 2016
4 2016
Name: cycle, dtype: int64
多层索引成dataframe类型
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filename = './files/presidential_polls.csv'
df1 = pd.read_csv(filename,usecols=['cycle', 'type', 'startdate','state','grade'],index_col = ['state','grade'])
print(df1.head())
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cycle type startdate
state grade
U.S. B 2016 polls-plus 10/25/2016
A+ 2016 polls-plus 10/27/2016
Virginia A+ 2016 polls-plus 10/27/2016
Florida A 2016 polls-plus 10/20/2016
U.S. B+ 2016 polls-plus 10/20/2016
跳过指定的行
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filename = './files/presidential_polls.csv'
df2 = pd.read_csv(filename,usecols=['cycle', 'type', 'startdate','state','grade'],skiprows=[1, 2, 3])
print(df2.head())
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cycle type state startdate grade
0 2016 polls-plus Florida 10/20/2016 A
1 2016 polls-plus U.S. 10/20/2016 B+
2 2016 polls-plus U.S. 10/22/2016 A
3 2016 polls-plus U.S. 10/26/2016 A-
4 2016 polls-plus Pennsylvania 10/25/2016 B-
pandas写csv文件
·to_csv里面的index参数作用?===可能是不要索引的意思。
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filename = './files/pandas_output.csv'
df.to_csv(filename, index=None)
三、jsON文件操作
json读操作
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import json
filename = './files/global_temperature.json'
with open(filename, 'r') as f_obj:
json_data = json.load(f_obj)
# 返回值是dict类型
print (type(json_data))
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print (json_data.keys())
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dict_keys(['description', 'data'])
json转CSV
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#print json_data['data'].keys()
print (json_data['data'].values())
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dict_values(['-0.1247', '-0.0707', '-0.0710', '-0.1481', '-0.2099', '-0.2220', '-0.2101', '-0.2559', '-0.1541', '-0.1032', '-0.3233', '-0.2552', '-0.3079', '-0.3221', '-0.2828', '-0.2279', '-0.0971', '-0.1232', '-0.2578', '-0.1172', '-0.0704', '-0.1471', '-0.2535', '-0.3442', '-0.4240', '-0.2967', '-0.2208', '-0.3767', '-0.4441', '-0.4332', '-0.3862', '-0.4367', '-0.3318', '-0.3205', '-0.1444', '-0.0747', '-0.2979', '-0.3193', '-0.2118', '-0.2082', '-0.2152', '-0.1517', '-0.2318', '-0.2161', '-0.2510', '-0.1464', '-0.0618', '-0.1506', '-0.1749', '-0.2982', '-0.1016', '-0.0714', '-0.1214', '-0.2481', '-0.1075', '-0.1445', '-0.1173', '-0.0204', '-0.0318', '-0.0157', '0.0927', '0.1974', '0.1549', '0.1598', '0.2948', '0.1754', '-0.0013', '-0.0455', '-0.0471', '-0.0550', '-0.1579', '-0.0095', '0.0288', '0.0997', '-0.1118', '-0.1305', '-0.1945', '0.0538', '0.1145', '0.0640', '0.0252', '0.0818', '0.0924', '0.1100', '-0.1461', '-0.0752', '-0.0204', '-0.0112', '-0.0282', '0.0937', '0.0383', '-0.0775', '0.0280', '0.1654', '-0.0698', '0.0060', '-0.0769', '0.1996', '0.1139', '0.2288', '0.2651', '0.3024', '0.1836', '0.3429', '0.1510', '0.1357', '0.2308', '0.3710', '0.3770', '0.2982', '0.4350', '0.4079', '0.2583', '0.2857', '0.3420', '0.4593', '0.3225', '0.5185', '0.6335', '0.4427', '0.4255', '0.5455', '0.6018', '0.6145', '0.5806', '0.6583', '0.6139', '0.6113', '0.5415', '0.6354', '0.7008', '0.5759', '0.6219', '0.6687', '0.7402', '0.8990'])
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# 转换key
year_str_lst = json_data['data'].keys()
year_lst = [int(year_str) for year_str in year_str_lst]
print (year_lst)
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[1880, 1881, 1882, 1883, 1884, 1885, 1886, 1887, 1888, 1889, 1890, 1891, 1892, 1893, 1894, 1895, 1896, 1897, 1898, 1899, 1900, 1901, 1902, 1903, 1904, 1905, 1906, 1907, 1908, 1909, 1910, 1911, 1912, 1913, 1914, 1915, 1916, 1917, 1918, 1919, 1920, 1921, 1922, 1923, 1924, 1925, 1926, 1927, 1928, 1929, 1930, 1931, 1932, 1933, 1934, 1935, 1936, 1937, 1938, 1939, 1940, 1941, 1942, 1943, 1944, 1945, 1946, 1947, 1948, 1949, 1950, 1951, 1952, 1953, 1954, 1955, 1956, 1957, 1958, 1959, 1960, 1961, 1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015]
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# 转换value
temp_str_lst = json_data['data'].values()
temp_lst = [float(temp_str) for temp_str in temp_str_lst]
print (temp_lst)
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[-0.1247, -0.0707, -0.071, -0.1481, -0.2099, -0.222, -0.2101, -0.2559, -0.1541, -0.1032, -0.3233, -0.2552, -0.3079, -0.3221, -0.2828, -0.2279, -0.0971, -0.1232, -0.2578, -0.1172, -0.0704, -0.1471, -0.2535, -0.3442, -0.424, -0.2967, -0.2208, -0.3767, -0.4441, -0.4332, -0.3862, -0.4367, -0.3318, -0.3205, -0.1444, -0.0747, -0.2979, -0.3193, -0.2118, -0.2082, -0.2152, -0.1517, -0.2318, -0.2161, -0.251, -0.1464, -0.0618, -0.1506, -0.1749, -0.2982, -0.1016, -0.0714
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