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ValueError : I/O operation on closed file
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Same error can raise by mixing: tabs + spaces.
with open('/foo', 'w') as f:
(spaces OR tab) print f <-- success
(spaces AND tab) print f <-- fail
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Can I add comments to a pip requirements file?
...hat begins with # is treated as a comment and ignored. Whitespace followed by a # causes the # and the remainder of the line to be treated as a comment.
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Total number of items defined in an enum
...atic method Enum.GetNames which returns an array representing the names of all the items in the enum. The length property of this array equals the number of items defined in the enum
var myEnumMemberCount = Enum.GetNames(typeof(MyEnum)).Length;
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make div's height expand with its content
...date the answer with a modern alternative using a new layout mode in CSS3 called Flexible boxes or Flexbox:
body {
margin: 0;
}
.flex-container {
display: flex;
flex-direction: column;
min-height: 100vh;
}
header {
background-color: #3F51B5;
color: #fff;
}
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Strings are objects in Java, so why don't we use 'new' to create them?
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By using String a = new String("abcd"), does it means two string with similar content are present in memory.
– changed
Jan 5 '10 at 21:54
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setting multiple column using one update
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Just add parameters, split by comma:
UPDATE tablename SET column1 = "value1", column2 = "value2" ....
See also: mySQL manual on UPDATE
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GROUP_CONCAT comma separator - MySQL
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SELECT id,GROUP_CONCAT(text SEPARATOR ' ') AS text FROM table_name group by id;
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don't fail jenkins build if execute shell fails
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Jenkins is executing shell build steps using /bin/sh -xe by default. -x means to print every command executed. -e means to exit with failure if any of the commands in the script failed.
So I think what happened in your case is your git command exit with 1, and because of the defaul...
What is the purpose of “!” and “?” at the end of method names?
Sometimes I see methods in Ruby that have "?" and "!" at the end of them, e.g:
5 Answers
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Why don't Java's +=, -=, *=, /= compound assignment operators require casting?
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A good example of this casting is using *= or /=
byte b = 10;
b *= 5.7;
System.out.println(b); // prints 57
or
byte b = 100;
b /= 2.5;
System.out.println(b); // prints 40
or
char ch = '0';
ch *= 1.1;
System.out.println(ch); // prints '4'
or
char ch = 'A';
ch *= 1.5...