Tag：range
-
Time：2021-5-8
A series of articles： Review Manual (1): data types Review Manual (2): variables and constants Review Manual (3): operators Review Manual (4): process control Boolean type Range: true; false; transformation:If it is false, it is true in all other cases var_ dump(boolval(0)); // bool(false) integer Range: //64 bit signed integer range, out of range converted […]
-
Time：2021-5-3
Abstract:When using spark SQL to perform ETL task, an error is reported when reading a table: “IOException: totalvaluecount = = 0”, but there is no exception when writing the table. This article is shared from Huawei cloud community《It’s time to upgrade your parquet: IOException: totalvaluecount = = 0》Author: wzhfy. 1. Problem description When using spark […]
-
Time：2021-4-17
Django uses or condition query: from django.db.models import Q User.objects.filter(Q(state=0) | Q(state=1)) Django query keywords: __ Exact equals like ‘AAA’__ Iexact is exactly the same as ignore case like ‘AAA’__ Contains contains like% AAA%__ Icontains contains ignore case like ‘% AAA%’, but for SQLite, the effect of contains is equivalent to icontains.__ GT greater than__ […]
-
Time：2021-4-15
preface The combination of for range in go can easily traverse an array or slice, but in some cases, it is likely to be “pit” when using for range func main() { arr1 := []int{1, 2, 3} arr2 := make([]*int, len(arr1)) for i, v := range arr1 { arr2[i] = &v } for _, v […]
-
Time：2021-4-13
Throw a question Question 1: in our daily development, we all encounter interface class requests, various third-party interfaces, and internal interfaces. How can we maintain these interface quick requests conveniently and quickly? Question 2: in the face of a third-party interface, remember when docking, do you think you can’t find it in the subsequent search? […]
-
Time：2021-3-26
[email protected] quick get start const mongoose = require(‘mongoose’); /*Connect to database*/ mongoose.connect (‘ mongodb://localhost/mytest ‘{usenewurlparser: true}); // if there is no mytest database, it will be created by itself let db = mongoose.connection; //If a connection error occurs db.on (‘error’, ()=>{ console.error (‘connection error ‘)}; //If the connection is successful db.once (‘open’, ()=>{ console.log (‘connected […]
-
Time：2021-3-17
What is Maven Maven is a cross platform project management tool, which mainly serves for project construction, dependency management and project information management based on Java platform. What is construction In addition to writing source code, we spend a considerable part of our time every day compiling, running unit tests, generating documents, packaging and deploymentstructure（build）。 […]
-
Time：2021-3-11
What’s your understanding of media inquiry? Brief concept Media query consists of an optional media type andZeroorMultipleThe composition of an expression that limits the scope of a style sheet using media features, such as width, height, and color. Media query, add fromCSS3It allows content rendering to be tailored to a specific range of output devices […]
-
Time：2021-3-4
Basic application scenarios of redis Get the winning user ID. after it pops up randomly, the set does not exist Store the winning user ID in the activity to ensure that the same user won’t win twice [set] Store the fan list, value is the user ID of the fan, score is the follow time […]
-
Time：2021-3-2
statement1) This article collates the selfless contributions of Daniel and experts from the Internet. Please refer to the references for the specific references.2) This article is for academic exchange only, non-commercial. If a certain part violates everyone’s interests, please contact Haihan to delete it.3) The blogger is short of talent and learning. If there are […]
-
Time：2021-2-20
import pandas as pd gl=pd.read_csv(‘./pandas/data/game_logs.csv’) #Memory usage of data gl.info(memory_usage=’deep’) <class ‘pandas.core.frame.DataFrame’> RangeIndex: 171907 entries, 0 to 171906 Columns: 161 entries, date to acquisition_info dtypes: float64(77), int64(6), object(78) memory usage: 859.4 MB for dtype in [‘float64′,’object’,’int64′]: selected_dtype=gl.select_dtypes(include=[dtype]) memory_usage_b=selected_dtype.memory_usage(deep=True).mean() memory_usage_mb=memory_usage_b/1024/1024 print(‘[%s] memory usage %0.2f MB’ % (dtype,memory_usage_mb)) [float64] memory usage 1.29 MB [object] memory usage 9.50 […]
-
Time：2021-1-16
Get the administrative region getcity() of the current map map <span style=”background-color: #f5f5f5; color: #800000;”> *</span><span style=”background-color: #f5f5f5; color: #000000;”>{</span><span style=”background-color: #f5f5f5; color: #ff0000;”>margin</span><span style=”background-color: #f5f5f5; color: #000000;”>:</span><span style=”background-color: #f5f5f5; color: #0000ff;”>0</span><span style=”background-color: #f5f5f5; color: #000000;”>;</span><span style=”background-color: #f5f5f5; color: #ff0000;”>padding</span><span style=”background-color: #f5f5f5; color: #000000;”>:</span><span style=”background-color: #f5f5f5; color: #0000ff;”>0</span><span style=”background-color: #f5f5f5; color: #000000;”>;</span><span style=”background-color: #f5f5f5; color: […]
