Question

我有一个csv文件，该文件需要拆分为两个csv文件（file1.csv和file2.csv）。应当进行拆分-基于“名称”列。需要将70％的行写入file1.csv，将其余30％的行写入file2.csv。例如，有10行名为“ AAA”。因此，10行中的70％意味着需要将“ AAA”的前7行写入file1.csv，然后将其后3行写入file2.csv。这样，“名称”列下的所有名称都需要发生这种情况。如果获得十进制数字，则示例为0.7 x 9行= 6.3。然后前6行（四舍五入）到file1.csv，其余3行到file2.csv 如何使用Python代码完成此操作？谢谢https://fil.email/FPYB1RWd

Answer 1

读取整个csv文件并将内容存储在列表中。然后将类似的csv数据存储在临时列表中。存储后，从列表中提取70％的数据并将其写入文件，然后将剩余的数据写入另一个文件。

csv_data = []
with open ('file.csv') as file:
    csv_data.append(file.read())
csv_data = (''.join(csv_data)).split("\n")
header = csv_data[0]
csv_data = csv_data[1:]
temp_list = []
add_header = True
for i in csv_data:
    if len(temp_list) == 0:
        temp_list.append(i)
    elif i.split(',')[0] == temp_list[0].split(',')[0]:
        temp_list.append(i)
    else:
        file_length = len(temp_list)
        line_count = int((0.7*file_length)+1)
        if line_count == 1:
            with open("file1.csv","a+") as file1:
                if add_header:
                    add_header = False
                    file1.write(header+'\n')
                file1.write(temp_list[0]+'\n')
        else:
            seventy_perc_lines = temp_list[:line_count]
            thirty_perc_lines = temp_list[line_count:]
            if add_header:
                seventy_perc_lines.insert(0,header)
                thirty_perc_lines.insert(0,header)
                add_header = False
            with open("file1.csv","a+") as file1:
                for j in range(len(seventy_perc_lines)):
                    file1.write(seventy_perc_lines[j]+'\n')
            if len(thirty_perc_lines) != 0:
                with open("file2.csv","a+") as file2:
                    for j in range(len(thirty_perc_lines)):
                        file2.write(thirty_perc_lines[j]+'\n')
        temp_list = []
        temp_list.append(i)

file1.csv

file2.csv

注意：如果只有3行，此代码将在file1中添加所有3行，而对file2不添加任何内容。如果您想更改此行为，则需要编辑此代码。

Answer 2

很简单：制作一个带有记录列表的字典，在主题上循环根据两个输出文件之一列出并输出单个记录遵循OP指定的简单规则。

from csv import reader, writer

inp0 = reader(open(...))
out1 = writer(open(..., 'w'))
out2 = writer(open(..., 'w'))

column, d = 0, {}

for rec in inp0: d.setdefault(rec[column], []).append(rec)

for recs in d.values():
    l = round(0.7*len(recs))
    for n, rec in enumerate(recs):
        (out1 if n<l else out2).writerow(rec)

这里是使用IPyton会话对此方法进行的检查（仔细地编辑以减少空白）和一些人工数据

17:22:~ $ ipython
Python 3.7.3 (default, Mar 27 2019, 22:11:17)
Type 'copyright', 'credits' or 'license' for more information
IPython 7.5.0 -- An enhanced Interactive Python. Type '?' for help.
In [1]: from csv import reader, writer
   ...: from random import randrange, seed
   ...: seed(20190712)
In [2]: data = [','.join(str(randrange(10)) for _ in range(4)) for _ in range(200)]
In [3]: inf = reader(data)
In [4]: of1 = writer(open('dele1', 'w')); of2 = writer(open('dele2', 'w'))
In [5]: d = {}
In [6]: for record in inf:
   ...:     d.setdefault(record[0], []).append(record)
   ...: for key, records in d.items():
   ...:     l1 = round(0.7*len(records))
   ...:     for n, record in enumerate(records):
   ...:         (of1 if n<l1 else of2).writerow(records)
In [7]: Ctrl-D
Do you really want to exit ([y]/n)?
17:23:~ $ wc -l dele?
  140 dele1
   60 dele2
  200 total
17:24:~ $ rm dele?
17:24:~ $

如您所见，第一个文件获得原始记录的70％，而第二个获得剩余的30％。

Answer 3

“”“ 将您的原始文件名替换为your_file_name 使用此功能，该功能将拆分csv文件并保存。您可以更改拆分百分比以获取不同的文件大小 “”“

def split_csv("your_file_name.csv"):
    import pandas as pd
    df = pd.read_csv("your_file_name.csv")
    split_percent = 0.7
    df_length = int(len(df)*split_percent)
    df1 = df.iloc[:df_length,:]
    df2 = df.iloc[df_length:,:]
    df1.to_csv("file1.csv")
    df2.to_csv("file2.csv")

将CSV文件拆分为两个单独的文件python 3.7

3 个答案: