問(wèn)題描述

我有一個(gè) DataFrame.以下是兩個(gè)相關(guān)的列:一個(gè)是 int 的列，另一個(gè)是 str 的列.

I have a DataFrame. Two relevant columns are the following: one is a column of int and another is a column of str.

我知道如果我將 NaN 插入 int 列，Pandas 會(huì)將所有 int 轉(zhuǎn)換為 float 因?yàn)?int 沒(méi)有 NaN 值.

I understand that if I insert NaN into the int column, Pandas will convert all the int into float because there is no NaN value for an int.

但是，當(dāng)我將 None 插入 str 列時(shí)，Pandas 會(huì)將我的所有 int 轉(zhuǎn)換為 float 為好.這對(duì)我來(lái)說(shuō)沒(méi)有意義 - 為什么我在第 2 列中輸入的值會(huì)影響第 1 列?

However, when I insert None into the str column, Pandas converts all my int to float as well. This doesn't make sense to me - why does the value I put in column 2 affect column 1?

這是一個(gè)簡(jiǎn)單的工作示例(Python 2):

Here's a simple working example (Python 2):

import pandas as pd
df = pd.DataFrame()
df["int"] = pd.Series([], dtype=int)
df["str"] = pd.Series([], dtype=str)
df.loc[0] = [0, "zero"]
print df
print
df.loc[1] = [1, None]
print df

輸出是

   int   str
0    0  zero

   int   str
0  0.0  zero
1  1.0   NaN

有沒(méi)有辦法讓輸出如下:

Is there any way to make the output the following:

   int   str
0    0  zero

   int   str
0    0  zero
1    1   NaN

不將第一列重鑄為 int.

• 我更喜歡使用 int 而不是 float 因?yàn)閷?shí)際數(shù)據(jù)在該列是整數(shù).如果沒(méi)有解決方法，我只會(huì)使用 float.

• I prefer using int instead of float because the actual data in that column are integers. If there's not workaround, I'll just use float though.

我不喜歡重鑄，因?yàn)樵谖业膶?shí)際代碼中，我不需要
存儲(chǔ)實(shí)際的dtype.

I prefer not having to recast because in my actual code, I don't
store the actual dtype.

我還需要逐行插入數(shù)據(jù).

I also need the data inserted row-by-row.

推薦答案

如果你設(shè)置dtype=object，你的系列就可以包含任意數(shù)據(jù)類(lèi)型:

If you set dtype=object, your series will be able to contain arbitrary data types:

df["int"] = pd.Series([], dtype=object)
df["str"] = pd.Series([], dtype=str)
df.loc[0] = [0, "zero"]
print(df)
print()
df.loc[1] = [1, None]
print(df)

   int   str
0    0  zero
1  NaN   NaN

  int   str
0   0  zero
1   1  None

這篇關(guān)于阻止 Pandas 將 int 轉(zhuǎn)換為 float的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！