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Redis消息通知系统的实现 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...时处理，那么很容易就崩溃了，此时可以使用一个队列来保存待处理的登录用户，如此一来顶多是反应慢点，但不会崩溃。
Redis的LIST数据类型可以很自然的创建一个队列，代码如下：
<?php
$redis = new Redis;
$redis->connect('/tmp/re...
Sorting multiple keys with Unix sort
...
Here is one to sort various columns in a csv file by numeric and dictionary order, columns 5 and after as dictionary order
~/test>sort -t, -k1,1n -k2,2n -k3,3d -k4,4n -k5d sort.csv
1,10,b,22,Ga
2,2,b,20,F
2,2,b,22,Ga
2,2,c,19,Ga
2,2,c,19,Gb,hi
2,2,c,19,Gb,hj
2,...
Pandas every nth row
...came up with when using the index was not viable ( possibly the multi-Gig .csv was too large, or I missed some technique that would allow me to reindex without crashing ).
Walk through one row at a time and add the nth row to a new dataframe.
import pandas as pd
from csv import DictReader
def make_...
How is mime type of an uploaded file determined by browser?
...70 (kPrimaryMappings and kSecondaryMappings).
An example: when uploading a CSV file from a Windows system with Microsoft Excel installed, Chrome will report this as application/vnd.ms-excel. This is because .csv is not specified in the first hard-coded list, so the browser falls back to the system r...
How to do what head, tail, more, less, sed do in Powershell? [closed]
... Holy cow, this is maxing out my CPU to do a -last 2 on a 1GB CSV. Hot beverage: ☕
– mlissner
Feb 19 '13 at 19:28
...
Lazy Method for Reading Big File in Python?
..., you can to use the file object itself as lazy generator:
with open('big.csv') as f:
for line in f:
process(line)
However, I once ran into a very very big (almost) single line file, where the row separator was in fact not '\n' but '|'.
Reading line by line was not an option, but I ...
Change one value based on another value in pandas
...re.
Assuming you can load your data directly into pandas with pandas.read_csv then the following code might be helpful for you.
import pandas
df = pandas.read_csv("test.csv")
df.loc[df.ID == 103, 'FirstName'] = "Matt"
df.loc[df.ID == 103, 'LastName'] = "Jones"
As mentioned in the comments, you c...
Create an empty data.frame
...ames)
Alternatively specifying the col.names as a string:
df <- read.csv(text="Date,File,User", colClasses = colClasses)
Thanks to Richard Scriven for the improvement
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How can I transform string to UTF-8 in C#?
...
Use the below code snippet to get bytes from csv file
protected byte[] GetCSVFileContent(string fileName)
{
StringBuilder sb = new StringBuilder();
using (StreamReader sr = new StreamReader(fileName, Encoding.Default, true))
{
St...
Include headers when using SELECT INTO OUTFILE?
...ment with lucek's answer and export dynamically table with columns name in CSV :
--If your table has too many columns
SET GLOBAL group_concat_max_len = 100000000;
--Prepared statement
SET @SQL = ( select CONCAT('SELECT * INTO OUTFILE \'YOUR_PATH\' FIELDS TERMINATED BY \',\' OPTIONALLY ENCLOSED BY \...