Python使用pandas库读取csv文件，并分组统计的一个例子

代码：

# coding=gbk
# 从HostWrites.csv读取数据并分组统计

import pandas
import datetime

print "\r\n从 HostWrites.csv 读取数据并分组统计\r\n"

excel = pandas.read_csv("D:\Program Files\CrystalDiskInfo8_2_0\Smart\KXG6AZNV512G TOSHIBA39HS1002TMFQ\HostWrites.csv", header=None)

dates = []
kv = {}
# for row in excel.iterrows():
for row in excel.tail(100).values:
    time = pandas.to_datetime(row[0])
    value = row[1]
    date = datetime.datetime.strftime(time, "%Y-%m-%d")

    if date not in kv:
        dates.append(date)
    kv[date] = value

last = None
delta = 0
lst = []
for date in dates:
    if last is not None:
        delta = kv[date] - last
    last = kv[date]

    today = datetime.datetime.strftime(datetime.datetime.now(), "%Y-%m-%d")
    yesterday = datetime.datetime.strftime(datetime.datetime.now() + datetime.timedelta(-1), "%Y-%m-%d")

    if delta > 50 or date == today or date == yesterday:
        lst.append((date, kv[date], delta))

print "日期".ljust(12, " "), "固态硬盘写入量".ljust(16, " "), "增量"

index = 0
for item in lst:
    index += 1
    if len(lst) - index < 20:
        print str(item[0]).ljust(13, " "), str(item[1]).ljust(15, " "), item[2]

raw_input("输入任意字符退出：")

输出：