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/bin/sh: pushd: not found
...d by child processes. (A hypothetical pushd command might do the chdir(2) call and then start a new shell, but ... it wouldn't be very usable.) pushd is a shell builtin, just like cd.
So, either change your script to start with #!/bin/bash or store the current working directory in a variable, do yo...
'float' vs. 'double' precision
...cand, and an exponent.
Because of this encoding, many numbers will have small changes to allow them to be stored.
Also, the number of significant digits can change slightly since it is a binary representation, not a decimal one.
Single precision (float) gives you 23 bits of significand, 8 bits of...
How to print a groupby object
...like a bug to me. I created an issue.
But a groupby operation doesn't actually return a DataFrame sorted by group. The .head() method is a little misleading here -- it's just a convenience feature to let you re-examine the object (in this case, df) that you grouped. The result of groupby is separat...
Change auto increment starting number?
In MySQL, I have a table, and I want to set the auto_increment value to 5 instead of 1 . Is this possible and what query statement does this?
...
SEH stack 结构探索（1）--- 从 SEH 链的最底层（线程第1个SEH结构）说起 -...
...是什么时候构建的，我在线程启动例程找到答案：ntdll32!_RtlUserThreadStart()里。0:000:x86> uf ntdll32!_Rt...线程的第 1 个 SEH 结构是什么时候构建的，我在线程启动例程找到答案：ntdll32!_RtlUserThreadStart() 里。
0:000:x86> uf ntdll32!_RtlU...
Python Progress Bar
...can ignore it by using warnings.simplefilter("ignore"), but it will ignore all warnings in your code after that.
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Select first row in each GROUP BY group?
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On Oracle 9.2+ (not 8i+ as originally stated), SQL Server 2005+, PostgreSQL 8.4+, DB2, Firebird 3.0+, Teradata, Sybase, Vertica:
WITH summary AS (
SELECT p.id,
p.customer,
p.total,
ROW_NUMBER() OVER(PARTITION BY p.cus...
How do I check if a variable exists?
...have nested functions, variables in outer scopes. If you want to check for all of them, you're probably best off triggering NameError after all.
– Petr Viktorin
Jun 10 '14 at 20:18
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How do I print the type or class of a variable in Swift?
...y<String>.self)")
Which outputs:
String(myvar0.dynamicType) -> __NSCFConstantString
String(myvar1.dynamicType) -> PureSwiftClass
String(myvar2.dynamicType) -> Int
String(myvar3.dynamicType) -> String
String(Int.self) -> Int
String((Int?).self -> Optional&...
How to get a key in a JavaScript object by its value?
...pt object, which I use as an associative array. Is there a simple function allowing me to get the key for a value, or do I have to iterate the object and find it out manually?
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