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What does the “Just” syntax mean in Haskell?
...r integer functions that are meant to return Natural numbers (for example, String.indexOf - when a substring is not found, the returned index is commonly designed to be negative)
return a special value (pointer): NULL or some such
silently return without doing anything: for example, lend could be wr...
In-memory size of a Python structure
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@AlexMartelli Hi Alex! .. Why minimum size of a char in python is 25 bytes. >>> getsizeof('a') gives 25 and >>> getsizeof('ab') gives 26 `
– Grijesh Chauhan
Jan 17 '13 at 5:13
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How to display pandas DataFrame of floats using a format string for columns?
... think you'll have to pre-modify the dataframe (converting those floats to strings):
import pandas as pd
df = pd.DataFrame([123.4567, 234.5678, 345.6789, 456.7890],
index=['foo','bar','baz','quux'],
columns=['cost'])
df['foo'] = df['cost']
df['cost'] = df['cost']...
How to append rows to an R data frame
...<- function(n){
df <- data.frame(x = numeric(n), y = character(n), stringsAsFactors = FALSE)
for(i in 1:n){
df$x[i] <- i
df$y[i] <- toString(i)
}
df
}
Here's a similar approach, but one where the data.frame is created as the last step.
# Use preallocated vectors
f4 <...
Convert a string to an enum in C#
What's the best way to convert a string to an enumeration value in C#?
25 Answers
25
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Difference between 'new operator' and 'operator new'?
...ething like your own container, you can call operator new directly, like:
char *x = static_cast<char *>(operator new(100));
It's also possible to overload operator new either globally, or for a specific class. IIRC, the signature is:
void *operator new(size_t);
Of course, if you overloa...
Where to put include statements, header or source?
...def.h> in the header file.
Your function uses strlen. Then #include <string.h> in the source file.
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Get value of c# dynamic property via string
I'd like to access the value of a dynamic c# property with a string:
11 Answers
11
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ActiveRecord: List columns in table from console
...ou can just type the model name:
> User
gives:
User(id: integer, name: string, email: string, etc...)
In rails four, you need to establish a connection first:
irb(main):001:0> User
=> User (call 'User.connection' to establish a connection)
irb(main):002:0> User.connection; nil #call ...
Changing variable names in Vim
...nvar()
expand("<cword>") gets the word under the cursor. The search string uses % for file-scope, and the \(\W\) patterns look for non-word characters at the boundary of the word to replace, and save them in variables \1 and \2 so as to be re-inserted in the replacement pattern.
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