读取 csv 文件 unicodeescape 时出错

Question

我有这个程序

import csv

with open("C:\Users\frederic\Desktop\WinPython-64bit-3.4.4.3Qt5\notebooks\scores.txt","r") as scoreFile:
    # write = w, read = r, append = a
    scoreFileReader = csv.reader(scoreFile)
    scoreList = []
    for row in scoreFileReader:
        if len (row) != 0:
            scoreList = scoreList + [row]

scoreFile.close()

print(scoreList)

---

为什么会出现此错误？

与 open("C:\Users\frederic\Desktop\WinPython-64bit-3.4.4.3Qt5\notebooks\scores.txt","r") 作为分数文件： ^ SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \UXXXXXXXX escape.

Answer 1

您需要使用带有 Windows 样式文件名的原始字符串：

with open(r"C:\Users\frederic\Desktop\WinPython-64bit-3.4.4.3Qt5\notebooks\scores.txt", 'r') as scoreFile:
         ^^

否则，Python 的字符串引擎会认为 \U 是 Unicode 转义序列的开始 - 当然在这种情况下不是。

---

另外，还要小心你的scoreFile.close() 没用：

with 语句替换了 try 和 catch。它也是 块后自动关闭文件。这意味着您可以删除 scoreFile.close() 行。

另外，你可以换行if len(row) != 0 根据PEP8：

对于序列，（字符串，列表，元组），使用空的事实 序列是错误的。

是：如果不是 seq： 如果序列：

否：如果 len(seq): 如果不是 len(seq):

最后一件事，你的for loop 也不好，阅读csv 你最好先从doc 复制一个例子！

with open('eggs.csv', 'rb') as csvfile:
    spamreader = csv.reader(csvfile, delimiter=' ', quotechar='|')
    for row in spamreader:
       print ', '.join(row)

Answer 2

你可以试试这个：

import csv
import io

def guess_encoding(csv_file):
    """guess the encoding of the given file"""
    with io.open(csv_file, "rb") as f:
        data = f.read(5)
    if data.startswith(b"\xEF\xBB\xBF"):  # UTF-8 with a "BOM"
        return ["utf-8-sig"]
    elif data.startswith(b"\xFF\xFE") or data.startswith(b"\xFE\xFF"):
        return ["utf-16"]
    else:  # in Windows, guessing utf-8 doesn't work, so we have to try
        try:
            with io.open(csv_file, encoding="utf-8") as f:
                preview = f.read(222222)
                return ["utf-8"]
        except:
            return [locale.getdefaultlocale()[1], "utf-8"]

encodings = guess_encoding(r"C:\Users\frederic\Desktop\WinPython-64bit-3.4.4.3Qt5\notebooks\scores.txt")[0])

# then your code with 
with open(r"C:\Users\frederic\Desktop\WinPython-64bit-3.4.4.3Qt5\notebooks\scores.txt","r", encoding=encodings[0]) as scoreFile: