相关疑难解决方法(0)

给定文件:

$ cat test.csv 
a,b,c,NULL,d
e,f,g,h,i
j,k,l,m,n

第3栏被视为的地方str.

当我在列上执行字符串函数时,pandas已将NULLstr作为NaNfloat 读取:

>>> import pandas as pd
>>> df = pd.read_csv('test.csv', names=[0,1,2,3,4], dtype={0:str, 1:str, 2:str, 3:str, 4:str})

>>> df[3].apply(str.strip)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.5/site-packages/pandas/core/series.py", line 2355, in apply
    mapped = lib.map_infer(values, f, convert=convert_dtype)
  File "pandas/_libs/src/inference.pyx", line 1569, in pandas._libs.lib.map_infer (pandas/_libs/lib.c:66440)
TypeError: descriptor 'strip' requires a 'str' object but received a 'float'

核实:

>>> for i in …