transistor | Python web scraping framework for intelligent use cases | Scraper library
kandi X-RAY | transistor Summary
kandi X-RAY | transistor Summary
Transistor, a Python web scraping framework for intelligent use cases.
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Top functions reviewed by kandi - BETA
- Start a fake web page
- Sets the status
- Open fake page text
- Sets the response content
- Return a generator of all cookies
- Creates a local copy of a cookie file
- Create a cookie
- Open a new crawler
- Reuse a crawler session
- Builds the distribution
- Process a task
- Submit the selected button
- Return a list of all the workgroups
- Gets the US day and time from the USD row
- Rename an item
- Opens a URL using the stateful API
- Get the cookies from the server
- Create a lua script
- Publish a task as a task
- Writes the item to the feed
- Write the results to disk
- Spawn a new spider
- Select the current form
- Prepares the scraper data for export
- Spawn a scraper
- Delete crawler sessions
transistor Key Features
transistor Examples and Code Snippets
Community Discussions
Trending Discussions on transistor
QUESTION
First time poster, so I apologize if I don't do things correctly. I am also new to React so bare with me, I will do my best to describe the problem.
I have a dataset that consists of school classes in json format. I am using axios to grab the data. The data consists of an array of objects which contains information about each class. I want to break up the classes so that they are separated into 4 different arrays based on what school year you are in (freshman, sophomore, junior, senior). I then want to display these classes on my web app.
Here is the code below:
...ANSWER
Answered 2022-Apr-03 at 22:32You must not modify the states directly as you are trying with freshman.push(item), instead use setFreshman([...freshman, item])
But in your case, this won't work because the app only updates the states after all forEach loop, so it will keep getting the initial state (the empty array) from the states and adding the current item, the only one in the end.
So one solution is using temporary variables to keep the items and once forEach has finished you update the states.
QUESTION
I'm trying to build a small hygrometer based on the DHT11 and I'm having a bit of an "issue" with the code size. I want to run it on an Attiny45 and it's a wee bit too big (352 bytes too big to be exact). I am aware that I could just use an Attiny85 and have space to spare or don't use a bootloader and barely fit it in (94%) but I kind of want to make my life harder than it needs to be and figure out how to reduce size since it'll probably come in handy in the future. Treat it as a learning experience if you will.
What it's supposed to do:
- Read DHT11 input
- Display results on 2 two-digit 7-segment displays (so I guess 4 7-segments in total)
- Go to sleep most of the time to preserve battery
- Wake up every 8 seconds to update sensor values (without turning on the display)
- Wake up on a button press to display the values for humidity and temperature
Side note: 7-segments are adressed via two 74HC595s of which I am using 7 outputs each for the displays and 1 each for a transistor that connects the display in question to GND. There's a schematic at the bottom if you're interested.
As pointed out, my main issue is code size so if anyone has any tips on how to reduce that (or any other tips how to improve the code) please let me know.
I hope I'm asking the question properly, if not please let me know.
Compiler output:
...ANSWER
Answered 2021-Nov-09 at 12:55Okay so thanks to the input of Mat I tried substituting the DHT11 library with something more sleek, which took me a while to get up and running. I ended up using this as a base, edited around a bit and commented heavily for my benefit. I added my updated code below for anyone interested (thanks for pointing out the correct highlighting issue), there's also a github with the rest of the design files.
Seems the library is really heavy, as the compiler output shows:
Compiler output:
QUESTION
I want to read the below CSV file into read_csv, due to the special characters in the CSV file , cant read the file properly, missing special characters in the column names in the data frame , and data is going here and there, but excel data is showing properly. can you help to fix this issue, want to skip 5 rows and read the remaining data as it is and rename the column name
CSV file:-
$$PROGRAM$$ transistor.csv
$$DEVICE$$ 1
$$LOT$$ lot
$$DATE$$ 7/28/2021
$$FORMAT$$ ,SERIAL,COND=Temp,COND=vdd
1,BA1,25,1.2,7/12/201
1,BA2,25,1.2
1,BA2,25,1.2
1,BA3,25,1.2
ANSWER
Answered 2021-Jul-28 at 12:40I think the problem is that your first row of data actually contains 5 values while your header only has 4 column names (the name for the date column is missing).
You can try to skip the header and provide column labels:
QUESTION
I'm writing some code to simulate a computer at the transistor level. The emulator boils down to a graph where each node is a transistor, and each edge is a wire connecting any two transistor nodes on the graph. This graph is cyclic, and transistor nodes may be connected to themselves.
To run a single "step" of the emulator, two separate functions are run:
- Each wire edge is processed, setting the input of its target node from the output of its source node. Each wire is visited exactly once each step, but a transitor may be visited multiple times.
- Each transistor node output state is updated from its input's states (how is outside the scope of this question, I'm pretty sure I'm doing it efficiently).
I believe I have the second step optimised, but I need help making the first step more efficient.
ImplementationThe code looks roughly like this:
...ANSWER
Answered 2021-Apr-06 at 22:04This is a hard problem to solve in general. The paper Vertex Reordering for Real-World Graphs and Applications: An Empirical Evaluation gives a good overview of various reordering algorithms and their effects on performance and locality. The paper in general weighs in favor of Rabbit-order based algorithms and variations thereof. Tuning for your specific case will depend on cache size, data size, branching factor, partitioning behavior, etc.
However, if you're looking for something that works decently well and isn't too hard to implement, I'd recommend the Reverse Cuthill-McKee (RCM) algorithm.
QUESTION
I have a rich text document (.rtf) that has notes separated by dates. It follows the format below:
2021-4-6
Some notes
Hyperlink
More text
2021-4-5
Notes notes notes
I'd like to split the document so that there is a different file for each date with the corresponding notes saved and the date as the file name. The split command seemed close to what i wanted but it doesn't seem to be able to account for the variable amount of text and lines for each day. Would a bash script work for this? I'm new to this so forgive me if the answer is obvious. Edit: the document contains some leading spaces and blank lines.
An example input file:
2020-11-15
How to properly use a NanoVNA V2 Vector Network Analyzer (Tutorial) - YouTube - VNA NanoVNA
Impedence matching an antenna Reflection VNA vs Spectrum Analyzer? Usually impedence of 50 ohms VSWR Meter SWR - Standing Wave Ratio SWR = 1 means there is no reflected power
2020-11-11
Superheterodyne receiver - Wikipedia - A superheterodyne receiver, often shortened to superhet, is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF) which can be more conveniently processed than the original carrier frequency. Protected Cell Unprotected Cell Logic Gates from Transistors: Transistors and Boolean Logic - YouTube -
Would be split into two files:
2020-11-15.rtf
2020-11-15
How to properly use a NanoVNA V2 Vector Network Analyzer (Tutorial) - YouTube - VNA NanoVNA
Impedence matching an antenna Reflection VNA vs Spectrum Analyzer? Usually impedence of 50 ohms VSWR Meter SWR - Standing Wave Ratio SWR = 1 means there is no reflected power
2020-11-11.rtf
...2020-11-11
Superheterodyne receiver - Wikipedia - A superheterodyne receiver, often shortened to superhet, is a type of radio receiver that uses frequency mixing to convert a received signal to a fixed intermediate frequency (IF) which can be more conveniently processed than the original carrier frequency. Protected Cell Unprotected Cell Logic Gates from Transistors: Transistors and Boolean Logic - YouTube -
ANSWER
Answered 2021-Apr-06 at 17:55awk to the rescue!
QUESTION
The following data represent the lifetimes (in hours) of a sample of 40 transistors:
...ANSWER
Answered 2021-Feb-19 at 00:56I think you can use data frame directly and then get the frequency for each value.
To convert your list to dataframe use the below code:
QUESTION
I am getting a little bit deeper in exploring the STM32's MCU and I went bare metal. I am using an STM32F103C8T6 BluePill.
Just to make sure I'm fully understanding what is going on, what is the nature of the addresses of the MCU? I mean, for my board, the RCC boundary address is 0x4002 1000 - 0x4002 13FF and by creating a custom named pointer to this address and type casing this "0x40021000" to be treated as an actual address by the compiler, is this an address of an actual register?
I mean what I understood is that the MCU has 32bit registers, those registers have addresses, those addresses are the addresses of the registers and each 32bit register in the MCU has a unique address, a physical one! And therefore to manipulate a specific register we create a pointer to the address of that register and then dereferencing the pointer and change the register it is pointing to.
For example, the RCC address starts at "0x40021000" and this address is of the register 0x0000XX83 (where X is undefined as per the reference manual), Am I right? Do those registers actually have addresses in the MCU so they can be accessed and manipulated? If so, are those registers bits are just transistors where when setting a bit in that register to 1 the transistor turns on?
Also if what I understood was correct, does that mean that the Reset Values are the actual register values which have addresses (as in registers are analogous to variables e.g x,y, etc.. and there addresses are those in the reference manual as in RCC address = 0x40021000 and dereferencing this address gives us 0x0000XX83 ??
I know I might have confused you but this is the best I can explain! Thank you in advance.
...ANSWER
Answered 2021-Feb-09 at 22:45Addresses are addresses on the bus*. When the compiler generates an instruction for the processor to read an address (LDR) it asks the bus to fetch what is at that address. Similarly a write instruction (STR) tells the bus what the address is and what data it wants to put there.
At the other end of the bus could be anything, but in most cases it will be either memory or a memory-mapped peripheral register. This could have any number of bits, but the most you can access in one go is 32. This is because the width of the bus is 32-bits. The datasheet lists the address ranges used by each peripheral, and the reference manual says what purpose of each peripheral register is.
In your example the RCC is a peripheral, its address range is 0x40021000-0x400213FF. The first register in the RCC is RCC_CR, which has address offset 0x00, making its address equal to 0x40021000. 0x0000XX83 is the value of the RCC_CR register at boot.
There are another set of registers which instructions can access directly. These are the processor core registers. Because they are not accessed through the bus they do not have an address. Most of the processor core registers have 32-bits and that is why the STM32 is called a 32-bit microcontroller.
(*in a Harvard architecture part like the Cortex-M3 used in STM32F1 there are actually several buses sharing an address space but as a beginner I would suggest you can overlook that.)
In terms of transistors, each bit in a register is usually made of more than 1 transistor. Often 6 transistors are wired together to make a flip-flop which represents a single bit.
QUESTION
Recently I've been trying to use a wired Xbox 360 controller to interface with my Arduino Uno (via Processing) that I'm using in a test circuit to control two brushed motors. I came across this video that uses the library to control a single servo motor along with videos made by the library's author. I made a few modifications to the code (from the first link) just to support the two motors, and it works (sort of). The only problem is that it accepts input from my Bluetooth mouse instead of the Xbox controller which are both connected to my laptop's USB ports. I set the text configuration file so that "Button 0" and "Button 2" -which correspond to the A and X buttons respectively- make two pins on the Arduino go high which feed into the bases of two transistors that control the motors. Instead, the left mouse button and scroll wheel button on my Bluetooth mouse controls these outputs.
I'm a bit confused about why this is happening and I've tried a few different things to resolve the issue. I thought that when creating the configuration file (with a program that comes with the library) I accidentally choose my mouse as the input device, so I made another configuration file just to make sure that this wasn't the case, though I'm not exactly sure what in the configuration file indicates the correct device to use. Maybe I'm missing something extremely obvious, I just know that I need a second set of eyes to look things over for me. If you have experience with this library your help would be much appreciated, thank you.
/////////////////////////////////////////////////////////////////////////////////////////////////////////
Configuration File:
...ANSWER
Answered 2020-Dec-31 at 00:53UPDATE: I was able to fix the problem after looking at some example code provided by the library that I was previously unaware of. In my defense, there is little support for this library and the video that I watched didn't use the line of code that I found in the example. I hope that this benefits someone in the future.
I ended up changing this:
QUESTION
Is there some simple way to avoid shorting the pins of a FET?
...ANSWER
Answered 2020-Sep-08 at 07:24I am not sure to understand what you want to achieve, but
- use
shortonly if you need to add poles or labels, otherwise--is easier to type; - use the anchors of the components.
tikzis automatically loaded bycircuitikz, and that one has a mandatory argument (the voltage direction standard, look at the manual and at the wanings! ;-).
So a first change could be this:
QUESTION
Preamble: after working a couple of years as application developer, the world of the software engineering became more obscure than it was before. The reason is that the real stuff is hidden under zillions layers of abstractions: OS, frameworks, etc. The young generation is deprived of the pleasure of working with PDP-like machines where all programming was done via electrical switch toggling. Another problem is the ephemeral nature of modern programming languages. Once there was Python 2.x, now it is deprecated and there is Python 3.x which in its turn will be deprecated in a couple of months. Idem for other languages. ANSI C looks like the Pyramid of Cheops: it was there in 70's and I don't doubt it will be there after the Sun will become a red dwarf.
It seems that now the only way to understand the interaction between the hardware and the software is to play with embedded development. From the pedagogical point of view physical chips are very handy because they allow to tackle the most difficult part of C language, namely pointers. When coding in OS environment, */& notation is still very confusing because it refers to some location somewhere inside of the virtual memory. And before you will got the understanding of what is the virtual memory, you have to read a couple of monographs about OS development, etc. You may find it stupid but I do really want to know which transistor is holding my bit right now. At least, I can wire physical pin voltage to programming abstractions.
Currently I am working with Atmel chips and WinAVR package because of numerous textbooks and accessible hardware. Though all books promise to teach AVR coding using plain C, the reality is that all pointers are hidden behind macros like PORTA, DDRB, etc. All code examples include header file 'io.h' which in its turn refers to other header files specific for a given chip like 'iomx8.h'. So far, I cannot find any macros definition in these headers. The code to increase the voltage on the physical pin 14 on Atmega168 looks like
...ANSWER
Answered 2020-Aug-26 at 01:50From a memory-mapping standpoint: The general purpose registers, special function+I/O registers, and SRAM share non-overlapping ranges a single address space, as described in datasheets for various processors in the AVR series. All of your pointers will reference this memory space, unless annotated as pointers to PROGMEM (which will cause different instructions to be emitted). The reference will be made without any sort of virtual memory mapping.
For example, the ATtiny 25/45/85 has the following map shown on page 18:
Your linker is aware of this memory map and will place variables accordingly. For example, a global variable declared in one of your compilation units will end up in an address above 0x0060 in the example device described above, so that it ends up in the SRAM.
From an instruction encoding standpoint: Although there is one address space, there is special functionality reserved for certain important regions. For example, IN and OUT instructions have six bits in their instruction encoding which can be used to directly refer to one of the 64 addresses within [0x20, 0x5F).
The IN and OUT instructions are unique in their ability to load and store to a fixed address encoded directly in the instruction, since the normal load and store instructions require an indirect load with the 'Z' register being loaded first.
As a result, when the compiler sees memory operations to a fixed I/O register, it may generate these more efficient instructions. However, a normal load/store via a pointer will have the same effect (although with different numbers of clock cycles required). For extended I/O registers that didn't fit into the first 64 (e.g. OSCCAL on an atmega328p), normal load/store instructions will always be generated.
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Vulnerabilities
No vulnerabilities reported
Install transistor
You can use transistor like any standard Python library. You will need to make sure that you have a development environment consisting of a Python distribution including header files, a compiler, pip, and git installed. Make sure that your pip, setuptools, and wheel are up to date. When using pip it is generally recommended to install packages in a virtual environment to avoid changes to the system.
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