## bitcoin core – public key generated when importing PK different from original pub key

I used bitcoin core (latest 0.19) to create some addresses offline. When I dumped the privkey I was surprised to see all of them starting with L2 (and the addresses with 3), but I went for it. I take note of the private keys/addresses.

Next day, I import one of the privkeys into another bitcoin core wallet, it scans, but the noted address never shows up in my receiving address. But still it added another address to my list (starts with 1B).

So I also added this privkey into an electrum wallet. And surprise, that same address is showing up, not the original one that I got when I created the pair.

What’s happening? Is that due to the L2 type?

## 8 – Re-order node fields in views generated from ID

I have a content type with fields: title, hours_worked, work_done.

I’ve created a view that gets the node ID from URL and outputs the fields of the target node: hours_worked and work_done. How do I introduce the ability to re-order which of the fields comes first in a drag and drop manner.

It’s similar to the functionality you get in Draggableviews/sortableiews/weight modules which are for re-ordering list of nodes but this requirement is for fields of specific node.

## Are symbols automatically generated when defining a variable in the global context and what are symbols?

Abstract: I have noticed something really tricky with Mathematica and the documentation for symbols is short on clearing the confusion. It likely reveals what symbols are but it’s not very prominent. I know unique symbols are created inside Modules but are they also generated every time we define regular functions and variables?

About The Code: I did a simple test with `abc = 123`. The output for `?abc` gives a grayed out `Symbol` and `SymbolName` produces an error message. Does this mean it is not a symbol?

``````abc = 123
?abc
SymbolName[abc]
``````

Four Questions:

1. Are system functions symbols?
2. Are user defined functions symbols?
3. Are user defined variables symbols?
4. What are symbols and are they automatically generated?

## python – Merging Generated PDF Pages Using PyPDF

currently working on a script which automatically fills up a fillable pdf file. Current challenge is that right now, all generated scripts are stored on multiple pdf files and what I wanted to do is to have them merged into a single PDF file instead of generating multiple files. This is the current script which generated multiple files:

``````from PyPDF2 import PdfFileWriter, PdfFileReader, PdfFileMerger
from PyPDF2.generic import BooleanObject, NameObject, IndirectObject

def set_need_appearances_writer(writer: PdfFileWriter):
try:
catalog = writer._root_object
# get the AcroForm tree
if "/AcroForm" not in catalog:
writer._root_object.update({
NameObject("/AcroForm"): IndirectObject(len(writer._objects), 0, writer)})

need_appearances = NameObject("/NeedAppearances")
writer._root_object("/AcroForm")(need_appearances) = BooleanObject(True)
return writer

except Exception as e:
print('set_need_appearances_writer() catch : ', repr(e))
return writer

for key in final10.keys():
infile = "new4-Copy.pdf"
pdf = PdfFileReader(open(infile, "rb"), strict=False)
if "/AcroForm" in pdf.trailer("/Root"):
pdf.trailer("/Root")("/AcroForm").update(
{NameObject("/NeedAppearances"): BooleanObject(True)})

pdf2 = PdfFileWriter()
set_need_appearances_writer(pdf2)
if "/AcroForm" in pdf2._root_object:
pdf2._root_object("/AcroForm").update(
{NameObject("/NeedAppearances"): BooleanObject(True)})

field_dictionary = final10(key)
pdf2.updatePageFormFieldValues(pdf2.getPage(0), field_dictionary)

outfile = '{}.pdf'.format(final10(key)('courier_id'))
a.append(outfile)
outputStream = open(outfile, "wb")
pdf2.write(outputStream)
``````

## Want to add Placeholder to Dynamically Generated Field Angular Material

I have an Angular Reactive form in which the input fields are generated dynamically
I want to change the placeholder of input fields which are dynamically generated
based upon what user has selected in the first textbox.

So Suppose User typed anything in first textbox so based upon that i want to change the value of Second textbox and so on..

Please note all the input fields are dynamically generated so i cannot just update the placeholder like this:
somePlaceholder : string = “new value”;

## ag.algebraic geometry – Finitely generated commutative rings with the same profinite completion

Let $$R_1$$ and $$R_2$$ be two finitely generated commutative rings. Assume that their profinite completions are isomorphic: $$widehat{R_1}cong widehat{R_2}$$.

Suppose that $$R_1$$ is a domain. Does it imply that $$R_2$$ is a domain as well?

The isomorphism between $$widehat{R_1}$$ and $$widehat{R_2}$$ is equivalent to the existence of a bijection $$phi: operatorname{maxSpec}(R_1)to operatorname{maxSpec}(R_2)$$ between the sets of maximal ideals, such that for all $$Min operatorname{maxSpec}(R_1)$$ the corresponding completions $$(R_1)_{(M)}$$ and $$(R_2)_{(phi(M))}$$ are isomorphic.

## What is the purpose of the (TOKEN) generated by (JWT)

I have used `JWT` features on my web development. Then it will generate the `TOKEN` after the users logging-in, and it works perfectly fine. But now I don’t know what to do next after the `TOKEN` is generated. Can anyone explain to me the purpose of this `TOKEN`? Thanks in advance.

## seo – How can a search engine crawl a dynamically generated website?

Short answer: That PHP code is run on the server before sending the response to the crawler, so by the time the page reaches the crawler, all that info is already populated.

For sites written using server-side languages such as your example, here’s the full lifecycle when a user visits a page:

1. The user’s browser sends an HTTP request to the server for a certain path (such as `/an/example/page/`).

2. The server receives the request and determines the appropriate server-side code to run to generate the page. It executes this code, if any (or none if it’s a static site).

3. The server sends the final generated, by that point static HTML page back to the user’s browser.

Note that all the code is finished running on the server before the server actually sends any information back to the user’s browser (or a web crawler).

Things are a little different when the page is generated in part by client-side code (JavaScript) instead, which is a topic for a different discussion.

## bitcoin core – Is the intex db downloaded from peers or generated locally?

When the user start the Bitcoin client for the first time, it will download the whole blockchain.
But what about the block index (blkindex.dat in older versions) ?
Is it donwloaded from peers just like the blockchain or generated locally from the downloaded blockchain?
Then, does it depend upon the implementation (or version) or will the answer be the same for Bitcoin, Litecoin, or other random fork?
The version I talk about is an old fork that is still using blkindex.dat.

## general topology – What topologies on \$ X \$ can be generated by selecting \$ F \$, a set of functions in \$ mathbb {R} \$, and making them continuous?

Let $$varepsilon$$ denotes the empty assembly.

Let $$X$$ to be a topological space with topology $$T$$.

Let $$langle B rangle$$ denote closure under arbitrary unions, including unions of zero elements, and finite intersections of a set of sets, $$B$$.

Let $$T _ { mathbb {R}}$$ denote the standard topology on the reals.

Which topologies can be generated by selecting $$F$$, a set of cards of $$X$$ at $$mathbb {R}$$, declaring them arbitrarily continuous, then calculating the inverse images of the elements of $$T _ { mathbb {R}}$$.

For example, I can get the standard topology on $$mathbb {R} ! times ! mathbb {R}$$ by choosing the two functions $$f_1$$ and $$f_2$$ below

$$f_1 (x, y) = x$$
$$f_2 (x, y) = y$$

IT $$langle f ^ {- 1} _1 (T _ { mathbb {R}}), f ^ {- 1} _2 (T _ { mathbb {R}}) rangle$$ gives me the topology I want. I can build any epsilon ball $$mathbb {R} ! times ! mathbb {R}$$ that I want by bringing together a countable set of open squares. The epsilon balls form a basis for the standard topology on $$mathbb {R} ! times ! mathbb {R}$$, so I'm done.

However, we cannot generate the Sierpiński topology, $${ varepsilon, {0 }, {0, 1 } }$$. In addition, the only finite topologies that we can generate by selecting functions in $$mathbb {R}$$ are discrete topologies.

Any potential function $$f$$ must send $$0$$ to a single real number and $$1$$ to a single real number and each real number is in an open set.

What topologies can we generate by choosing a set of functions $$mathbb {R}$$ to be continuous and then leveraging the existing topological structure of $$mathbb {R}$$?