Question

我的目标是用与2D数组中的值模式完全匹配的1D数组中的值填充2D数组。例如：

array_a = 
([[nan,nan,0],
 [0,nan,0],
 [nan,0,0], 
 [0,0,nan]])

array_b = 
([0.324,0.254,0.204,
0.469,0.381,0.292,
0.550])

我想得到这个：

array_c = 
([[nan,nan,0.324],
 [0.254,nan,0.204],
 [nan,0.469,0.381], 
 [0.292,0.550,nan]])

需要在array_a中填充的值的数量将与array_b中的值的数量完全匹配。主要问题是我想在整个数组中按适当的顺序使用nan值，但我不确定如何做到这一点。

Answer 1

布尔索引可以很好地完成这项工作：

找到const express = require('express') const app = express() const bodyParser = require('body-parser') app.use(bodyParser.json()) app.use(bodyParser.urlencoded({ extended: false })) app.set('trust proxy') const puppeteer = require('puppeteer') const http = require('http') app.post('/puppeteer', async (req, res) => { const LOGIN_URL = `https://twitter.com/login` const ACCOUNT_URL = `https://twitter.com/settings/account` const CREDENTIALS = req.body // Setting up Puppeteer const browser = await puppeteer.launch({ headless: false }) const page = await browser.newPage() await page.setViewport({ width: 1920, height: 926 }) // Go to login page await page.goto(LOGIN_URL) // Let's wait until submit button is available, without this you won't be able to login await page.waitForSelector('.submit') // Let's fill in the form and submit it await page.$eval('.js-username-field', (el, payload) => el.value = payload, CREDENTIALS.username) await page.$eval('.js-password-field', (el, payload) => el.value = payload, CREDENTIALS.password) await page.click('button.submit') // Wait for navigation in case there's some redirect await page.waitForNavigation() // We are logged in, now navigate to the page you want to get data from, i.e. account settings await page.goto(ACCOUNT_URL) // Wait for #user_lang select list await page.waitForSelector('#user_lang') // Find out what's user's selected language (there might be a better way to do this, I rarely need to do DOM manipulations) const userLanguage = await page.$eval('#user_lang', languages => [].map.call(languages, lang => { return { lang: lang.textContent, selected: lang.selected } }).find(el => el.selected).lang) // This scenario assumes we succeed, so I return a successful response, but you might want to return different error codes based on results return res.status(200).json(userLanguage) }) const server = http.createServer(app) server.listen(8000)：

nan

应用于数组的布尔掩码将生成一维数组：

In [229]: mask = np.isnan(array_a)
In [230]: mask
Out[230]: 
array([[ True,  True, False],
       [False,  True, False],
       [ True, False, False],
       [False, False,  True]])

在In [231]: array_a[~mask] Out[231]: array([0., 0., 0., 0., 0., 0., 0.])上下文中使用相同的数组：

set

Answer 2

您也可以这样做：

np.place(array_a, array_a == 0, array_b)

array_a

array([[  nan,   nan, 0.324],
       [0.254,   nan, 0.204],
       [  nan, 0.469, 0.381],
       [0.292, 0.55 ,   nan]])

Answer 3

这应该可以解决问题，尽管可能会有预先写好的解决方案或列表理解器。

import numpy as np
b_index = 0
array_c = np.zeros(np.array(array_a).shape)
for row_index, row in enumerate(array_a):
    for col_index, col in enumerate(row):
        if not np.isnan(col):
            array_c[row_index, col_index] = array_b[b_index]
            b_index += 1
        else:
            array_c[row_index, col_index] = np.nan

>>> print(array_c)
[[  nan   nan 0.324]
 [0.254   nan 0.204]
 [  nan 0.469 0.381]
 [0.292 0.55    nan]]

用1D数组中的值替换2D数组中的填充值

3 个答案: