说明：
*csv与txt文件读写方式是一样的
*pandas内置10多种数据源读取函数，常见的就是csv和excel
*使用read_csv方法读取，文件名称尽量是英文
*参数较多，可以自行控制，但很多时候用默认参数
*读取csv时，注意编码，常用编码为utf-8、gbk、gbk2312和gb18030等
*使用to_csv方法快速保存
df=pd.read_csv('meal_order_info.csv',encoding='gbk')
df=pd.read_csv('meal_order_info.csv',encoding='gbk',nrows=10)
df.to_csv('df.csv',index=False)
import numpy as np
import pandas as pd
import os
#获取文件当前路径
os.getcwd()
'C:\\Users\\Administrator'
#更改文件当前路径
os.chdir('C:\\Users\\Administrator')
baby=pd.read_csv('Vehicle No.0_Fragment No.0.csv',encoding='utf-8')#注意编码格式，不同的文件用不同的格式
baby.head(5)#默认将第一行做表头即列标签，左边为行索引
time total_voltage total_current soc temp_max temp_min motor_voltage motor_current mileage
0 20180205195412 520.1 60 38 20 13 519 62 37918.5
1 20180205195422 521.2 32 38 20 13 521 36 NaN
2 20180205195432 521.1 43 38 20 13 521 46 NaN
3 20180205195442 523.8 38 38 20 13 522 41 NaN
4 20180205195452 528.3 -55 38 20 13 533 -118 NaN
order=pd.read_csv('Vehicle No.0_Fragment No.0.csv',encoding='gbk')
baby.head(5)
time total_voltage total_current soc temp_max temp_min motor_voltage motor_current mileage
0 20180205195412 520.1 60 38 20 13 519 62 37918.5
1 20180205195422 521.2 32 38 20 13 521 36 NaN
2 20180205195432 521.1 43 38 20 13 521 46 NaN
3 20180205195442 523.8 38 38 20 13 522 41 NaN
4 20180205195452 528.3 -55 38 20 13 533 -118 NaN
order.info()#输出字段的信息
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 212 entries, 0 to 211
Data columns (total 9 columns):
time 212 non-null int64
total_voltage 212 non-null float64
total_current 212 non-null int64
soc 212 non-null int64
temp_max 212 non-null int64
temp_min 212 non-null int64
motor_voltage 212 non-null int64
motor_current 212 non-null int64
mileage 1 non-null float64
dtypes: float64(2), int64(7)
memory usage: 15.0 KB
order=pd.read_csv('Vehicle No.0_Fragment No.0.csv',encoding='utf-8',dtype={'time':str,'soc':str})#更改表头的数据类型，object即是字符串类型，
order.head(5)
order.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 212 entries, 0 to 211
Data columns (total 9 columns):
time 212 non-null object
total_voltage 212 non-null float64
total_current 212 non-null int64
soc 212 non-null object
temp_max 212 non-null int64
temp_min 212 non-null int64
motor_voltage 212 non-null int64
motor_current 212 non-null int64
mileage 1 non-null float64
dtypes: float64(2), int64(5), object(2)
memory usage: 15.0+ KB
#只显示前100行
baby=pd.read_csv('Vehicle No.0_Fragment No.0.csv',encoding='utf-8',nrows=100)
#最多显示n列
pd.set_option('display.max_columns',5)
#最多显示n行
pd.set_option('display.max_rows',20)
#保存，一般不保存行索引
import os
os.getcwd()
baby.to_csv('a.csv',encoding='utf-8',index=False)