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How to estimate how much memory a Pandas' DataFrame will need?
I have been wondering... If I am reading, say, a 400MB csv file into a pandas dataframe (using read_csv or read_table), is there any way to guesstimate how much memory this will need? Just trying to get a better feel of data frames and memory...
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On design patterns: When should I use the singleton?
The glorified global variable - becomes a gloried global class. Some say breaking object-oriented design.
19 Answers
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搭建高可用mongodb集群（三）—— 深入副本集内部机制 - 大数据 & AI - 清...
...识；而一致性协议强调的是操作的顺序一致性，比如同时读写一个数据会不会出现脏数据。一致协议在分布式里有一个经典的算法叫“Paxos算法”，后续再介绍。
上面有个问题，就是所有从节点的最后操作时间都是一样怎么办...
Can iterators be reset in Python?
...y available.
As several answers rightly remarked, in the specific case of csv you can also .seek(0) the underlying file object (a rather special case). I'm not sure that's documented and guaranteed, though it does currently work; it would probably be worth considering only for truly huge csv file...
Create Pandas DataFrame from a string
...ringIO (python2) or io.StringIO (python3) and pass that to the pandas.read_csv function. E.g:
import sys
if sys.version_info[0] < 3:
from StringIO import StringIO
else:
from io import StringIO
import pandas as pd
TESTDATA = StringIO("""col1;col2;col3
1;4.4;99
2;4.5;200
3;4...
Load data from txt with pandas
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You can use:
data = pd.read_csv('output_list.txt', sep=" ", header=None)
data.columns = ["a", "b", "c", "etc."]
Add sep=" " in your code, leaving a blank space between the quotes. So pandas can detect spaces between values and sort in columns. Data co...
Open the file in universal-newline mode using the CSV Django module
I am trying to access a model.filefield in Django to parse a CSV file in Python using the csv module. It's working on Windows, but on Mac it gave me this:
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Trimming a huge (3.5 GB) csv file to read into R
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My try with readLines. This piece of a code creates csv with selected years.
file_in <- file("in.csv","r")
file_out <- file("out.csv","a")
x <- readLines(file_in, n=1)
writeLines(x, file_out) # copy headers
B <- 300000 # depends how large is one pack
while(length...
How is Pythons glob.glob ordered?
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My files were returned by glob something like:
myList = ["c:\tmp\x\123.csv", "c:\tmp\x\44.csv", "c:\tmp\x\101.csv", "c:\tmp\x\102.csv", "c:\tmp\x\12.csv"]
I sorted the list in place, to do this I created a function:
def sortKeyFunc(s):
return int(os.path.basename(s)[:-4])
This function ...
Specify custom Date format for colClasses argument in read.table/read.csv
...cify the Date format when using the colClasses argument in read.table/read.csv?
4 Answers
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