pandas：列的长度必须与键的长度相同
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pandas: columns must be same length as key
提问by ale19
I'm trying to re-format several columns into strings (they contain NaNs, so I can't just read them in as integers). All of the columns are currently float64, and I want to make it so they don't have decimals.
我正在尝试将几列重新格式化为字符串（它们包含 NaN，所以我不能将它们作为整数读入）。所有的列目前都是 float64，我想让它们没有小数。
Here is the data:
这是数据：
{'crash_id': {0: 201226857.0,
1: 201226857.0,
2: 2012272611.0,
3: 2012272611.0,
4: 2012298998.0},
'driver_action1': {0: 1.0, 1: 1.0, 2: 29.0, 3: 1.0, 4: 3.0},
'driver_action2': {0: 99.0, 1: 99.0, 2: 1.0, 3: 99.0, 4: 99.0},
'driver_action3': {0: 99.0, 1: 99.0, 2: 99.0, 3: 99.0, 4: 99.0},
'driver_action4': {0: 99.0, 1: 99.0, 2: 99.0, 3: 99.0, 4: 99.0},
'harmful_event1': {0: 14.0, 1: 14.0, 2: 14.0, 3: 14.0, 4: 14.0},
'harmful_event2': {0: 99.0, 1: 99.0, 2: 99.0, 3: 99.0, 4: 99.0},
'harmful_event3': {0: 99.0, 1: 99.0, 2: 99.0, 3: 99.0, 4: 99.0},
'harmful_event4': {0: 99.0, 1: 99.0, 2: 99.0, 3: 99.0, 4: 99.0},
'most_damaged_area': {0: 14.0, 1: 2.0, 2: 14.0, 3: 14.0, 4: 3.0},
'most_harmful_event': {0: 14.0, 1: 14.0, 2: 14.0, 3: 14.0, 4: 14.0},
'point_of_impact': {0: 15.0, 1: 1.0, 2: 14.0, 3: 14.0, 4: 1.0},
'vehicle_id': {0: 20121.0, 1: 20122.0, 2: 20123.0, 3: 20124.0, 4: 20125.0},
'vehicle_maneuver': {0: 3.0, 1: 1.0, 2: 4.0, 3: 1.0, 4: 1.0}}
When I try to convert those columns to string, this is what happens:
当我尝试将这些列转换为字符串时，会发生以下情况：
>> df[['crash_id','vehicle_id','point_of_impact','most_damaged_area','most_harmful_event','vehicle_maneuver','harmful_event1','harmful_event2','harmful_event3','harmful_event4','driver_action1','driver_action2','driver_action3','driver_action4']] = df[['crash_id','vehicle_id','point_of_impact','most_damaged_area','most_harmful_event','vehicle_maneuver','harmful_event1','harmful_event2','harmful_event3','harmful_event4','driver_action1','driver_action2','driver_action3','driver_action4']].applymap(lambda x: '{:.0f}'.format(x))
File "C:\Users\<name>\AppData\Local\Continuum\Anaconda3\lib\site-packages\pandas\core\frame.py", line 2376, in _setitem_array
raise ValueError('Columns must be same length as key')
ValueError: Columns must be same length as key
I've never seen this error before and feel like this is something simple...what am I doing wrong?
我以前从未见过这个错误，觉得这很简单……我做错了什么？
采纳答案by JAV
Your code runs for me with the dictionary you provided. Try creating a function to deal with the NaN cases separately; I think they are causing your issues.
您的代码使用您提供的字典为我运行。尝试创建一个函数来分别处理 NaN 情况；我认为他们导致了你的问题。
Something basic like below:
一些基本的东西如下：
def formatter(x):
if x == None:
return None
else:
return '{:.0f}'.format(x)
