pandas学习笔记打卡第一天

客官°小女子只卖身不卖艺 2022-11-27 03:19 271阅读 0赞

测试数据：fund\_result.csv

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1 pandas读取csv文件

import pandas as pd
    
    result = pd.read_csv(r'D:\python_project_lzz\fund_result.csv')
    print(result)

2 只读取部分行（前5行）

result = pd.read_csv(r'D:\python_project_lzz\fund_result.csv',nrows=5)
    print(result)

3 使用to\_csv方法导出为逗号分割的文件或其他符号分割

import pandas as pd
    
    data = pd.read_csv(r'D:\python_project_lzz\fund_result.csv',nrows=5)
    data.to_csv(r'D:\python_project_lzz\fund_result1.csv')

sep添加分割符号，想用什么用什么

data.to_csv(r'D:\python_project_lzz\fund_result1.csv',sep='|')

4 标注缺失值

data.to_csv(r'D:\python_project_lzz\fund_result1.csv',na_rep= 'null')

5默认行列标签都被写入，设置不写入

data.to_csv(r'D:\python_project_lzz\fund_result1.csv',index= False,header=False)

6 pandas读取csv数据

import csv
    f = open(r'D:\python_project_lzz\fund_result.csv',encoding='utf-8')
    reader = csv.reader(f)
    for line in reader:
        print(line)

7 对读取的数据做字典处理

import csv
    f = open(r'D:\python_project_lzz\fund_result.csv',encoding='utf-8')
    reader = csv.reader(f)
    lines = list(reader)
    header,values = lines[0],lines[1:]
    data_dict = {h:v for h ,v in zip(header,zip(*values))}
    print(data_dict)

8 读取csv，对分隔符，字符串引用，行终止符

class my_dialect(csv.Dialect):
        lineterminator =  '\n'
        delimiter = ','
        quotechar = '"'
        quoting = csv.QUOTE_MINIMAL
    reader = csv.reader(f,dialect=my_dialect)
    for i in reader:
        print(i)

9 json数据转换

#字典处理
    obj = """{"name":"111","pet":"222"}"""
    import json
    # 转Python
    result = json.loads(obj)
    print(result)
    # 转json
    asjson = json.dumps(result)
    print(asjson)

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