用Python检查文件是否为CSV格式

Question

有人能提供一个有效的方法来检查一个文件是否是CSV格式吗？用Python来实现。

Answer 1

Python有一个叫做csv模块的东西，你可以用它来解析不同类型的CSV文件。

Answer 2

补充一下gotgenes的回答：我发现检查那些不应该出现在csv文件中的不可打印字符也能取得不错的效果。

def is_csv(infile):
    try:
        with open(infile, newline='') as csvfile:
            start = csvfile.read(4096)

            # isprintable does not allow newlines, printable does not allow umlauts...
            if not all([c in string.printable or c.isprintable() for c in start]):
                return False
            dialect = csv.Sniffer().sniff(start)
            return True
    except csv.Error:
        # Could not get a csv dialect -> probably not a csv.
        return False

Answer 3

你可以尝试下面这样的做法，但仅仅因为你从 csv.Sniffer 得到了一个方言（也就是文件格式的某种特征），这并不能保证你手里的CSV文件就是有效的。

csv_fileh = open(somefile, 'rb')
try:
    dialect = csv.Sniffer().sniff(csv_fileh.read(1024))
    # Perform various checks on the dialect (e.g., lineseparator,
    # delimiter) to make sure it's sane

    # Don't forget to reset the read position back to the start of
    # the file before reading any entries.
    csv_fileh.seek(0)
except csv.Error:
    # File appears not to be in CSV format; move along