assign

(Based on this question ): One can override the __setattr__ magic method for an object to have additional instructions when an attribute of an object is set. As in: class MyClass(object): def __init__(self, attribute=None): object.__init__(self) self.attribute = attribute def __setattr__(self, name, value): self.__dict__[name] = value if name == 'attribute': print("attribute's value is modified to {}.".format( self.attribute)) if __name__ == '__main__': my_obj = MyClass(True) while True: my_obj.attribute = input() How can I catch a particular name assignment in the current script without using

In summary, I have a script for importing lots of data stored in several txt files. In a sigle file not all the rows are to be put in the same table (DF now switching to DT), so for each file I select all the rows belonging to the same DF, get DF and assign to it the rows. The first time I create a DF named ,say, table1 I do: name <- "table1" # in my code the value of name will depend on different factors # and **not** known in advance assign(name, someRows) Then, during the execution my code may find (in other files) other lines to be put in the table1 data frame, so: name <- "table" assign

I have a MySQL Database Table containing products and prices. Though an html form I got the product name in a certain php file. For the operation in this file I want to do I also need the corresponding price. To me, the following looks clear enough to do it: $price = mysql_query("SELECT price FROM products WHERE product = '$product'"); However, its echo returns: Resource id #5 instead a value like like: 59.95 There seem to be other options like mysqli_fetch_assoc mysqli_fetch_array But I can't get them to output anything meaningful and I don't know which one to use. Thanks in advance. You will

I am trying to create multiple scatter plot graphs in ggplot that have the same structure but with a different Y-value. I need them to be separate (and therefore not use facet_wrap) because in a later step I use grid_arrange to arrange different combinations of the graphs onto a single layout. Because of this, I need to create new names for each plot that reflect the y-value being plotted. Below is sample code, where month is the variable on the x-axis and I want three separate plots of month vs. the three additional variables (lag1_var, lag3_var and lag9_var). df <- data.frame (month= c(1, 2,

For example, from std::deque::operator = in C++ Reference: (1) Copy Assignment (const std::deque &other) Replaces the contents with a copy of the contents of other. If std::allocator_traits::propagate_on_container_copy_assignment() is true, the target allocator is replaced by a copy of the source allocator. If the target and the source allocators do not compare equal, the target (*this) allocator is used to deallocate the memory, then other's allocator is used to allocate it before copying the elements. If this->get_allocator() == other.get_allocator() , I can simply destroy and deallocate

There seems to be a minor difference between data.tabel's assignment by reference := in the standard to the functinal form. Standard form coerces RHS to vector, the functional form does not. A detail, but not documented as I believe. library(data.table) dt <- data.table(a = c('a','b','c')) v <- c('A','B','C') l <- list(v) all.equal(copy(dt)[, new := v], copy(dt)[, `:=` (new = v)]) # [1] TRUE all.equal(copy(dt)[, new := l], copy(dt)[, `:=` (new = l)]) # [1] "Datasets have different column modes. First 3: new(character!=list)" copy(dt)[, new := l][] # a new # 1: a A # 2: b B # 3: c C copy(dt)[,