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How to delete duplicate lines in a file without sorting it in Unix?
...e expression evaluates to true. The ++ increments seen so that seen[$0] == 1 after the first time a line is found and then seen[$0] == 2, and so on.
Awk evaluates everything but 0 and "" (empty string) to true. If a duplicate line is placed in seen then !seen[$0] will evaluate to false and the line ...
How can I get a list of locally installed Python modules?
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+100
Solution
Do not use with pip > 10.0!
My 50 cents for getting a pip freeze-like list from a Python script:
import pip
installed...
Convert the values in a column into row names in an existing data frame
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138
This should do:
samp2 <- samp[,-1]
rownames(samp2) <- samp[,1]
So in short, no there ...
How do you round to 1 decimal place in Javascript?
Can you round a number in javascript to 1 character after the decimal point (properly rounded)?
21 Answers
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How is set() implemented?
I've seen people say that set objects in python have O(1) membership-checking. How are they implemented internally to allow this? What sort of data structure does it use? What other implications does that implementation have?
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What is the difference between Python's list methods append and extend?
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append: Appends object at the end.
x = [1, 2, 3]
x.append([4, 5])
print (x)
gives you: [1, 2, 3, [4, 5]]
extend: Extends list by appending elements from the iterable.
x = [1, 2, 3]
x.extend([4, 5])
print (x)
gives you: [1, 2, 3, 4, 5]
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Linux下部署企业级邮件服务器(postfix + dovecot + extmail) - 开源 & Gith...
...邮件服务器，公司全部员工使用统一的域名，内网IP为：192.168.0.115
操作系统：RHEL5
所用软件列表：
mysql-5.5.20
postfix-2.9.1
courier-authlib-0.62.4.tar.bz2
extmail-1.2.tar.gz
extman-1.1.tar.gz
Unix-Syslog-1.1.tar.gz
perl-GD-2.35-1.el5.rf.i386....
Are trailing commas in arrays and objects part of the spec?
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212
Specs: ECMAScript 5 and ECMAScript 3
Section 11.1.5 in the ECMAScript 5 specification:
Obj...