已知某日国内部分城市的天气和气温数据（weather.xls）。按照温差等级表（weather.xls）降序排列后输出结果，并筛选出天气为“晴”且温差等级小于2的城市。使用Python语言

好的，这里我会使用Python中的pandas和xlrd库来读取和处理Excel文件，代码如下：

import pandas as pd
import xlrd

# 读取Excel文件
data = pd.read_excel('weather.xls', sheet_name='Sheet1')

# 读取温差等级表
workbook = xlrd.open_workbook('weather.xls')
sheet = workbook.sheet_by_name('Sheet2')
temp_diff_level = {}
for i in range(1, sheet.nrows):
    level = sheet.cell_value(i, 0)
    diff = sheet.cell_value(i, 1)
    temp_diff_level[level] = diff

# 计算温差并添加到DataFrame中
temp_diff = []
for i in range(len(data)):
    high_temp = data.iloc[i, 1]
    low_temp = data.iloc[i, 2]
    diff = high_temp - low_temp
    temp_diff.append(diff)
data['温差'] = temp_diff

# 根据温差等级排序
data = data.sort_values(by=['温差'], ascending=False)

# 筛选出天气为“晴”且温差等级小于2的城市
result = data[(data['天气'] == '晴') & (data['温差'] < temp_diff_level['2'])]

# 输出结果
print(result)

请将代码保存为.py文件运行即可。注意，需要安装pandas和xlrd库，可通过pip命令进行安装。