pandas ValueError：项目错误长度 907 而不是 2000
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ValueError: Item wrong length 907 instead of 2000
提问by Diganta Bharali
I have a csv file, that has 1000 columns. I need to read only the first 100 columns. I wrote this program for that:
我有一个 csv 文件，有 1000 列。我只需要阅读前 100 列。我为此编写了这个程序：
import pandas as pd
list = []
for i in range (1, 100):
list.append(i)
df = pd.read_csv('piwik_37_2016-07-08.csv',dtype = "unicode")
df = df[df.columns.isin(list)]
df.to_csv('abc.csv', index = False)
But I get error: ValueError: Item wrong length 907 instead of 2000. Can't figure out where I went wrong
但我收到错误：ValueError: Item wrong length 907 而不是 2000。不知道我哪里出错了
回答by juanpa.arrivillaga
There are a lot of things strange about your code. For example, there is no reason to iterate over the range object and update a list just to get a list of numbers. Just use list(range(1,100)).
你的代码有很多奇怪的地方。例如，没有理由迭代范围对象并更新列表只是为了获取数字列表。只需使用list(range(1,100)).
However, if you just need the first 100 columns in the csv, there is built-in functionality for what you are trying to do:
但是，如果您只需要 csv 中的前 100 列，则有内置功能可用于您尝试执行的操作：
df = pd.read_csv('piwik_37_2016-07-08.csv',dtype = "unicode", usecols = list(range(100)))
回答by Shahidur
Though its down voted, still answering as its a small correction in the code.
虽然它被否决了，但仍然作为代码中的一个小更正来回答。
import pandas as pd
l = list(range(0,100))
df = pd.read_csv('piwik_37_2016-07-08.csv',dtype = "unicode")
df = df.loc[:,df.columns.isin(l)]
df.to_csv('abc.csv', index = False)
