Question

我正在使用熊猫read_csv 3.8 Gig文本文件，该文件以竖线分隔，但是将文件读入内存时出错。

这是我的read_in_files()函数抛出的全部错误：

错误：

Reading in file C:\Users\cdabel\Desktop\_Temp\Master_Extract_Data_Mart_201909240935.txt
Traceback (most recent call last):
  File "<stdin>", line 10, in <module>
  File "<stdin>", line 7, in read_in_files
  File "c:\python36\lib\site-packages\pandas\io\parsers.py", line 685, in parser_f
    return _read(filepath_or_buffer, kwds)
  File "c:\python36\lib\site-packages\pandas\io\parsers.py", line 463, in _read
    data = parser.read(nrows)
  File "c:\python36\lib\site-packages\pandas\io\parsers.py", line 1154, in read
    ret = self._engine.read(nrows)
  File "c:\python36\lib\site-packages\pandas\io\parsers.py", line 2048, in read
    data = self._reader.read(nrows)
  File "pandas\_libs\parsers.pyx", line 879, in pandas._libs.parsers.TextReader.read
  File "pandas\_libs\parsers.pyx", line 894, in pandas._libs.parsers.TextReader._read_low_memory
  File "pandas\_libs\parsers.pyx", line 948, in pandas._libs.parsers.TextReader._read_rows
  File "pandas\_libs\parsers.pyx", line 935, in pandas._libs.parsers.TextReader._tokenize_rows
  File "pandas\_libs\parsers.pyx", line 2130, in pandas._libs.parsers.raise_parser_error
pandas.errors.ParserError: Error tokenizing data. C error: Unknown error in IO callback

此错误的可能原因是什么？可能与记忆有关吗？我该如何解决？我应该对这些数据进行分块吗？

我不怀疑RAM问题，因为在调用函数时我有7 GB以上的未使用RAM，如Windows 10 Task Manager性能监视器中所示。另外，我无法提供基础数据的任何示例，因为它是运行状况和PII数据。

这是我的代码的摘录：

import os
import pandas as pd

# File
filepath = "C:\\Temp\\datafile.txt"
filename_w_ext = "datafile.txt"

# Read in TXT file
def read_in_files(filepath, filename_w_ext):
    filename, file_ext = os.path.splitext(filename_w_ext)
    print('Reading in file {}'.format(filepath))
    with open(filepath, "r", newline='') as file:
        global df_data
        # Here's where it errors:
        df_data = pd.read_csv(file, dtype=str, sep='|')
        return df_data.columns.values.tolist(), df_data.values.tolist()

搜索此特定错误仅提供了熊猫Tokenizer code

中错误处理的源代码。

第583-612行：

static int parser_buffer_bytes(parser_t *self, size_t nbytes) {
    int status;
    size_t bytes_read;

    status = 0;
    self->datapos = 0;
    self->data = self->cb_io(self->source, nbytes, &bytes_read, &status);
    TRACE((
        "parser_buffer_bytes self->cb_io: nbytes=%zu, datalen: %d, status=%d\n",
        nbytes, bytes_read, status));
    self->datalen = bytes_read;

    if (status != REACHED_EOF && self->data == NULL) {
        int64_t bufsize = 200;
        self->error_msg = (char *)malloc(bufsize);

        if (status == CALLING_READ_FAILED) {
            snprintf(self->error_msg, bufsize,
                     "Calling read(nbytes) on source failed. "
                     "Try engine='python'.");
        } else {
            snprintf(self->error_msg, bufsize, "Unknown error in IO callback");
        }
        return -1;
    }

    TRACE(("datalen: %d\n", self->datalen));

    return status;
}

Answer 1

在功能更强大的服务器上进行测试后，我现在意识到此错误显然是由于该文件需要114列的4 GB文件需要25至35 GB的可用RAM。这实际上应该引发内存不足的错误，但是我认为RAM中增加的数量超过了Tokenizer代码检查内存即将耗尽的能力。

pandas“ pandas.errors.ParserError：标记数据出错。C错误：IO回调中发生未知错误”

错误：

这是我的代码的摘录：

第583-612行：

1 个答案: