我有一个清单：
citylist = ['New York', 'San Francisco', 'Los Angeles', 'Chicago', 'Miami']
和具有这些值的熊猫数据框 df1
first last city email
John Travis New York a@email.com
Jim Perterson San Franciso, Los Angeles b@email.com
Nancy Travis Chicago b1@email.com
Jake Templeton Los Angeles b3@email.com
John Myers New York b4@email.com
Peter Johnson San Franciso, Chicago b5@email.com
Aby Peters Los Angeles b6@email.com
Amy Thomas San Franciso b7@email.com
Jessica Thompson Los Angeles, Chicago, New York b8@email.com
我想计算城市列表中每个城市在数据框列“城市”中出现的次数：
New York 3
San Francisco 3
Los Angeles 4
Chicago 3
Miami …我有一个输入数据框，内容如下：
NAME TEXT
Tim Tim Wagner is a teacher.
Tim He is from Cleveland, Ohio.
Frank Frank is a musician.
Tim He like to travel with his family
Frank He is a performing artist who plays the cello.
Frank He performed at the Carnegie Hall last year.
Frank It was fantastic listening to him.
如果 NAME 列的连续行具有相同的值，我想连接 TEXT 列。
输出数据框：
NAME TEXT
Tim Tim Wagner is a teacher. He is from Cleveland, Ohio.
Frank Frank is a musician
Tim He …