将字典列表中的Python时间戳转换为日期

我有一个包含Python时间戳的字典列表。我需要将时间戳转换为常规日期。我本想用一个lamda表达式来做这个，但我无法让它工作。请参见下面的我的代码：

findMatchPlay(newData):
i = 0
compList=[]
for tPeriod in newData:
    member = tPeriod['username']
    url2 = 'https://api.chess.com/pub/player/{}/matches'.format(member)
    response = s.get(url2)
    response.raise_for_status()
    matches = response.json()
    for status in matches:
        for game in matches[status]:
            gString = ''.join(game['club'])
            if team in gString:
                i = i + 1
        compList.append({'player': member,'Date Joined': tPeriod['Date Joined'],
            'active': tPeriod['active'],
            'status': status, 'games played': i})
        compList[0]['Date Joined'] = compList[0]['Date Joined'].apply(lambda x:datetime.fromtimestamp(x))
        i = 0

上面的代码给出了以下错误：int'object没有属性'apply'

任何帮助都将不胜感激

compList[0]['Date Joined'] = compList[0]['Date Joined']

应该是

compList[0]['Date Joined'] = datetime.fromtimestamp(compList[0]['Date Joined'])

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好的，这是一个巨大的帮助，但我得到了以下错误：TypeError：需要一个整数（得到了类型datetime.datetime）。你能在tPeriod中发布值吗？我试图用像这个datetime这样的“int”来纠正错误。fromtimestamp（int（compList[0]['Date Joined']），但这不起作用。那是不恰当的。我想知道compList[0]['Date Joined']中的值是什么。tPeriod看起来像这样：{'Date Joined'：1547992205'active'：'weekly'，'username'：'buffalobill57'}{'Date Joined'：1547986304'active'：'weekly'，'username'：'knightburgler'}