我试图读取一个大的csv文件(aprox。6 GB)在熊猫和我得到一个内存错误:

MemoryError                               Traceback (most recent call last)
<ipython-input-58-67a72687871b> in <module>()
----> 1 data=pd.read_csv('aphro.csv',sep=';')

...

MemoryError: 

有什么帮助吗?


当前回答

如果您使用pandas将大文件读入块,然后逐行yield,这是我所做的

import pandas as pd

def chunck_generator(filename, header=False,chunk_size = 10 ** 5):
   for chunk in pd.read_csv(filename,delimiter=',', iterator=True, chunksize=chunk_size, parse_dates=[1] ): 
        yield (chunk)

def _generator( filename, header=False,chunk_size = 10 ** 5):
    chunk = chunck_generator(filename, header=False,chunk_size = 10 ** 5)
    for row in chunk:
        yield row

if __name__ == "__main__":
filename = r'file.csv'
        generator = generator(filename=filename)
        while True:
           print(next(generator))

其他回答

你可以尝试sframe,它和pandas有相同的语法,但是允许你操作比你的RAM大的文件。

函数read_csv和read_table几乎是一样的。但在程序中使用read_table函数时,必须分配分隔符“,”。

def get_from_action_data(fname, chunk_size=100000):
    reader = pd.read_csv(fname, header=0, iterator=True)
    chunks = []
    loop = True
    while loop:
        try:
            chunk = reader.get_chunk(chunk_size)[["user_id", "type"]]
            chunks.append(chunk)
        except StopIteration:
            loop = False
            print("Iteration is stopped")

    df_ac = pd.concat(chunks, ignore_index=True)

除了上面的答案,对于那些想要处理CSV然后导出到CSV、parquet或SQL的人来说,d6tstack是另一个不错的选择。您可以加载多个文件,它处理数据模式更改(添加/删除列)。核心支持已经被剔除。

def apply(dfg):
    # do stuff
    return dfg

c = d6tstack.combine_csv.CombinerCSV([bigfile.csv], apply_after_read=apply, sep=',', chunksize=1e6)

# or
c = d6tstack.combine_csv.CombinerCSV(glob.glob('*.csv'), apply_after_read=apply, chunksize=1e6)

# output to various formats, automatically chunked to reduce memory consumption
c.to_csv_combine(filename='out.csv')
c.to_parquet_combine(filename='out.pq')
c.to_psql_combine('postgresql+psycopg2://usr:pwd@localhost/db', 'tablename') # fast for postgres
c.to_mysql_combine('mysql+mysqlconnector://usr:pwd@localhost/db', 'tablename') # fast for mysql
c.to_sql_combine('postgresql+psycopg2://usr:pwd@localhost/db', 'tablename') # slow but flexible

如果你有一个csv文件,有数百万个数据条目,你想要加载完整的数据集,你应该使用dask_cudf,

import dask_cudf as dc

df = dc.read_csv("large_data.csv")

解决方案1:

使用大数据的熊猫

解决方案2:

TextFileReader = pd.read_csv(path, chunksize=1000)  # the number of rows per chunk

dfList = []
for df in TextFileReader:
    dfList.append(df)

df = pd.concat(dfList,sort=False)