将一个csv拆分为多个文件

Question

我有一个大约5000行的python csv文件，我想把它分成五个文件

我为它写了一个代码，但它不起作用

import codecs
import csv
NO_OF_LINES_PER_FILE = 1000
def again(count_file_header,count):
    f3 = open('write_'+count_file_header+'.csv', 'at')
    with open('import_1458922827.csv', 'rb') as csvfile:
        candidate_info_reader = csv.reader(csvfile, delimiter=',', quoting=csv.QUOTE_ALL)
        co = 0      
        for row in candidate_info_reader:
            co = co + 1
            count  = count + 1
            if count <= count:
                pass
            elif count >= NO_OF_LINES_PER_FILE:
                count_file_header = count + NO_OF_LINES_PER_FILE
                again(count_file_header,count)
            else:
                writer = csv.writer(f3,delimiter = ',', lineterminator='\n',quoting=csv.QUOTE_ALL)
                writer.writerow(row)

def read_write():
    f3 = open('write_'+NO_OF_LINES_PER_FILE+'.csv', 'at')
    with open('import_1458922827.csv', 'rb') as csvfile:


        candidate_info_reader = csv.reader(csvfile, delimiter=',', quoting=csv.QUOTE_ALL)

        count = 0       
        for row in candidate_info_reader:
            count  = count + 1
            if count >= NO_OF_LINES_PER_FILE:
                count_file_header = count + NO_OF_LINES_PER_FILE
                again(count_file_header,count)
            else:
                writer = csv.writer(f3,delimiter = ',', lineterminator='\n',quoting=csv.QUOTE_ALL)
                writer.writerow(row)

read_write()

上面的代码创建了许多内容为空的文件

如何将一个文件拆分为五个csv文件

Answer 1

python3友好的解决方案：

def split_csv(source_filepath, dest_folder, split_file_prefix,
                records_per_file):
    """
    Split a source csv into multiple csvs of equal numbers of records,
    except the last file.

    Includes the initial header row in each split file.

    Split files follow a zero-index sequential naming convention like so:

        `{split_file_prefix}_0.csv`
    """
    if records_per_file <= 0:
        raise Exception('records_per_file must be > 0')

    with open(source_filepath, 'r') as source:
        reader = csv.reader(source)
        headers = next(reader)

        file_idx = 0
        records_exist = True

        while records_exist:

            i = 0
            target_filename = f'{split_file_prefix}_{file_idx}.csv'
            target_filepath = os.path.join(dest_folder, target_filename)

            with open(target_filepath, 'w') as target:
                writer = csv.writer(target)

                while i < records_per_file:
                    if i == 0:
                        writer.writerow(headers)

                    try:
                        writer.writerow(next(reader))
                        i += 1
                    except StopIteration:
                        records_exist = False
                        break

            if i == 0:
                # we only wrote the header, so delete that file
                os.remove(target_filepath)

            file_idx += 1

Answer 2

我建议你不要发明轮子。有现成的解决办法。资料来源here

import os


def split(filehandler, delimiter=',', row_limit=1000,
          output_name_template='output_%s.csv', output_path='.', keep_headers=True):
    import csv
    reader = csv.reader(filehandler, delimiter=delimiter)
    current_piece = 1
    current_out_path = os.path.join(
        output_path,
        output_name_template % current_piece
    )
    current_out_writer = csv.writer(open(current_out_path, 'w'), delimiter=delimiter)
    current_limit = row_limit
    if keep_headers:
        headers = reader.next()
        current_out_writer.writerow(headers)
    for i, row in enumerate(reader):
        if i + 1 > current_limit:
            current_piece += 1
            current_limit = row_limit * current_piece
            current_out_path = os.path.join(
                output_path,
                output_name_template % current_piece
            )
            current_out_writer = csv.writer(open(current_out_path, 'w'), delimiter=delimiter)
            if keep_headers:
                current_out_writer.writerow(headers)
        current_out_writer.writerow(row)

像这样使用它：

split(open('/your/pat/input.csv', 'r'));

Answer 3

Python中的

使用readlines()和writelines()来执行此操作，下面是一个示例：

>>> csvfile = open('import_1458922827.csv', 'r').readlines()
>>> filename = 1
>>> for i in range(len(csvfile)):
...     if i % 1000 == 0:
...         open(str(filename) + '.csv', 'w+').writelines(csvfile[i:i+1000])
...         filename += 1

输出文件名将被编号为1.csv，2.csv。。。等等

来自终端

仅供参考，您可以使用split从命令行执行此操作，如下所示：

$ split -l 1000 import_1458922827.csv