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What does the star operator mean, in a function call?
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s = sum(1, 2)
The double star ** does the same, only using a dictionary and thus named arguments:
values = { 'a': 1, 'b': 2 }
s = sum(**values)
You can also combine:
def sum(a, b, c, d):
return a + b + c + d
values1 = (1, 2)
values2 = { 'c': 10, 'd': 15 }
s = sum(*values1, **values2)
w...
Only read selected columns
...able() to skip columns. Here the data in the first 7 columns are "integer" and we set the remaining 6 columns to "NULL" indicating they should be skipped
> read.table("data.txt", colClasses = c(rep("integer", 7), rep("NULL", 6)),
+ header = TRUE)
Year Jan Feb Mar Apr May Jun
1 2009...
What does collation mean?
What does collation mean in SQL, and what does it do?
9 Answers
9
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Add legend to ggplot2 line plot
... about legends in ggplot2. I managed to plot three lines in the same graph and want to add a legend with the three colors used. This is the code used
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What is the correct way to check for string equality in JavaScript?
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always Until you fully understand the differences and implications of using the == and === operators, use the === operator since it will save you from obscure (non-obvious) bugs and WTFs. The "regular" == operator can have very unexpected results due to ...
How can I reliably get an object's address when operator& is overloaded?
...(); is declared, then func is a reference to a function taking no argument and returning no result. This reference to a function can be trivially converted into a pointer to function -- from @Konstantin: According to 13.3.3.2 both T & and T * are indistinguishable for functions. The 1st one is a...
How to update a git clone --mirror?
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This is the command that you need to execute on the mirror:
git remote update
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How to make input type= file Should accept only pdf and xls
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You could do so by using the attribute accept and adding allowed mime-types to it. But not all browsers do respect that attribute and it could easily be removed via some code inspector. So in either case you need to check the file type on the server side (your second que...
Python - abs vs fabs
...n (if it can't, it throws an exception). It then takes the absolute value, and returns the result as a float.
In addition to floats, abs() also works with integers and complex numbers. Its return type depends on the type of its argument.
In [7]: type(abs(-2))
Out[7]: int
In [8]: type(abs(-2.0))
Out...
How do you debug a regex? [closed]
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You buy RegexBuddy and use its built in debug feature. If you work with regexes more than twice a year, you will make this money back in time saved in no time. RegexBuddy will also help you to create simple and complex regular expressions, and...