# 方法一:定位到table,并获得table中所有得tr元素
menu_table = self.driver.find_element_by_xpath("//div[@class='datagrid-view1']/div[2]/div/table")
rows = menu_table.find_elements_by_tag_name('tr')
# python 得len()函数返回对象(字符、列表、元组)得长度或者元素得个数
before_add_numbers = len(rows)
print(before_add_numbers)
# 方法二:根据元素直接获取
rowlist = driver.find_elements_by_xpath("//*[contains(@class,'editable-empty')]")
driver.find_elements_by_xpath("//*[contains(@class,'editable-empty')]")[1].click()
print(len(rowlist))