<p>尝试:</p>
<pre><code>import numpy as np
import pandas as pd
# Sample 100 rows of data to determine dtypes.
df_test = pd.read_csv(filename, nrows=100)
float_cols = [c for c in df_test if df_test[c].dtype == "float64"]
float32_cols = {c: np.float32 for c in float_cols}
df = pd.read_csv(filename, engine='c', dtype=float32_cols)
</code></pre>
<p>首先读取100行数据的样本(根据需要修改)以确定每列的类型。</p>
<p>它创建了一个“float64”列的列表,然后使用字典理解创建一个字典,其中这些列作为键,“np.float32”作为每个键的值。</p>
<p>最后,它使用“c”引擎读取整个文件(为列分配dtype所必需),然后将float32\u cols字典作为参数传递给dtype。</p>
<pre><code>df = pd.read_csv(filename, nrows=100)
>>> df
int_col float1 string_col float2
0 1 1.2 a 2.2
1 2 1.3 b 3.3
2 3 1.4 c 4.4
>>> df.info()
<class 'pandas.core.frame.DataFrame'>
Int64Index: 3 entries, 0 to 2
Data columns (total 4 columns):
int_col 3 non-null int64
float1 3 non-null float64
string_col 3 non-null object
float2 3 non-null float64
dtypes: float64(2), int64(1), object(1)
df32 = pd.read_csv(filename, engine='c', dtype={c: np.float32 for c in float_cols})
>>> df32.info()
<class 'pandas.core.frame.DataFrame'>
Int64Index: 3 entries, 0 to 2
Data columns (total 4 columns):
int_col 3 non-null int64
float1 3 non-null float32
string_col 3 non-null object
float2 3 non-null float32
dtypes: float32(2), int64(1), object(1)
</code></pre>