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?
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
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。
其他回答
您可以将数据读入为块,并将每个块保存为pickle。
import pandas as pd
import pickle
in_path = "" #Path where the large file is
out_path = "" #Path to save the pickle files to
chunk_size = 400000 #size of chunks relies on your available memory
separator = "~"
reader = pd.read_csv(in_path,sep=separator,chunksize=chunk_size,
low_memory=False)
for i, chunk in enumerate(reader):
out_file = out_path + "/data_{}.pkl".format(i+1)
with open(out_file, "wb") as f:
pickle.dump(chunk,f,pickle.HIGHEST_PROTOCOL)
在下一步中,读入pickle并将每个pickle附加到所需的数据框架中。
import glob
pickle_path = "" #Same Path as out_path i.e. where the pickle files are
data_p_files=[]
for name in glob.glob(pickle_path + "/data_*.pkl"):
data_p_files.append(name)
df = pd.DataFrame([])
for i in range(len(data_p_files)):
df = df.append(pd.read_pickle(data_p_files[i]),ignore_index=True)
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)
在使用chunksize选项之前,如果你想确定你想要在@unutbu提到的分块for循环中写入的进程函数,你可以简单地使用nrows选项。
small_df = pd.read_csv(filename, nrows=100)
一旦确定流程块准备好了,就可以将其放入整个数据帧的分块for循环中。
下面是一个例子:
chunkTemp = []
queryTemp = []
query = pd.DataFrame()
for chunk in pd.read_csv(file, header=0, chunksize=<your_chunksize>, iterator=True, low_memory=False):
#REPLACING BLANK SPACES AT COLUMNS' NAMES FOR SQL OPTIMIZATION
chunk = chunk.rename(columns = {c: c.replace(' ', '') for c in chunk.columns})
#YOU CAN EITHER:
#1)BUFFER THE CHUNKS IN ORDER TO LOAD YOUR WHOLE DATASET
chunkTemp.append(chunk)
#2)DO YOUR PROCESSING OVER A CHUNK AND STORE THE RESULT OF IT
query = chunk[chunk[<column_name>].str.startswith(<some_pattern>)]
#BUFFERING PROCESSED DATA
queryTemp.append(query)
#! NEVER DO pd.concat OR pd.DataFrame() INSIDE A LOOP
print("Database: CONCATENATING CHUNKS INTO A SINGLE DATAFRAME")
chunk = pd.concat(chunkTemp)
print("Database: LOADED")
#CONCATENATING PROCESSED DATA
query = pd.concat(queryTemp)
print(query)
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)