Python: URL 数据到 csv reader

Question

我正在尝试将 url 请求的结果转换为 Python 中的 CSV reader object。输出看起来不错，但出现以下错误：

    for study_id, sample_id, run_id in reader:
ValueError: not enough values to unpack (expected 3, got 1)

首先我请求数据并将其转换为字符串数据：

req = urllib.request.Request(url=url_get_project_runs, headers={'Content-Type': 'text/plain'})
        res = urllib.request.urlopen(req)
        dec_res =  res.read().decode()
        sys.stderr.write(str(dec_res)) --> for the print see below
        return dec_res

印刷品将给出：

ERP001736,ERS494374,ERR598958
ERP001736,ERS494394,ERR598963
ERP001736,ERS494431,ERR598964
ERP001736,ERS494445,ERR599170
ERP001736,ERS494488,ERR598996
ERP001736,ERS494518,ERR598976
ERP001736,ERS494559,ERR598986
ERP001736,ERS494579,ERR599078
ERP001736,ERS494616,ERR598944
ERP001736,ERS494628,ERR599001
ERP001736,ERS488919,ERR1701760

这对我来说似乎很好，因为这些项目是用逗号分隔的，并且 "rows" 是完整的。但是，如果我将其用作 CSV reader 的输入并尝试打印三列，如下所示：

reader = csv.reader(dec_res, delimiter=',')
        for study_id, sample_id, run_id in reader:
            print(study_id + ", " + sample_id + ", " + run_id)

会出现以下错误： ValueError: not enough values to unpack (expected 3, got 1)

我进一步测试了一些代码以发现问题：

 for row in reader:
            sys.stderr.write(str(row))

这将给出：

['E']['R']['P']['0']['0']['1']['7']['3']['6']['', '']['E']['R']['S']['4']['7']...etc

Answer 1

您正在将 str 传递给 csv reader 并且它需要逐行迭代。 str 是逐个字符的可迭代对象。用 StringIO 包裹你的字符串或使用 splitlines （或任何其他方式提供逐行迭代）。

import csv
from io import StringIO

dec_res = """ERP001736,ERS494374,ERR598958
ERP001736,ERS494394,ERR598963
ERP001736,ERS494431,ERR598964
ERP001736,ERS494445,ERR599170
ERP001736,ERS494488,ERR598996
ERP001736,ERS494518,ERR598976
ERP001736,ERS494559,ERR598986
ERP001736,ERS494579,ERR599078
ERP001736,ERS494616,ERR598944
ERP001736,ERS494628,ERR599001
ERP001736,ERS488919,ERR1701760"""

reader = csv.reader(StringIO(dec_res), delimiter=',')
#reader = csv.reader(dec_res.splitlines(), delimiter=',')

for study_id, sample_id, run_id in reader:
    print(study_id + ", " + sample_id + ", " + run_id)

Python: URL 数据到 csv reader

Python: URL data to csv reader

python

csv

url

urllib