pandas学习笔记打卡第一天

测试数据：fund_result.csv 

 

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)