eval | 易学教程

DBI: raiseerror in eval

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问题 This question refers to this comment from Ikegami: [...] But if you're going to put an eval around every statement, just use RaiseError => 0. [...] in this thread. What do I gain, if I set RaiseError to 0 in such situations? #!/usr/bin/env perl use warnings; use 5.10.1; use DBI; my $db = 'my_test_sqlite_db.sqlite'; open my $fh, '>', $db or die $!; close $fh or die $!; my ( $dbh, $sth ); eval { $dbh = DBI->connect( "DBI:SQLite:dbname=$db", "", "", {} ); }; if ( $@ ) { print $@ }; my $table =

Bind List of object array to ListView in ASP.NET

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问题 I am breaking my head to fix an issue. I have a method that returns a List<Object[]> . Each object[] in the List contains the following: object[0]=Id; object[1]=Name; Now, I am looking for a way to bind this List to a ListView in a custom ItemTemplate which would look as follows: <asp:Label runat="server" ID="lblId" Text="Here want to do an Eval/Bind for object[0]"></asp:Label> <asp:Label runat="server" ID="lblName" Text="Here want to do an Eval/Bind for object[1]"></asp:Label> Any

Json之语法，格式

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JSON 文本格式在语法上与创建 JavaScript 对象的代码相同。由于这种相似性，无需解析器，JavaScript 程序能够使用内建的 eval() 函数，用 JSON 数据来生成原生的 JavaScript 对象。 JSON语法规则: 数据在名称/值对仲数据由逗号分隔花括号保存对象方括号保存数组 JSON 名称/值对介绍 "name":"张飞", "age":23 Json的值可以是：数字(整数或浮点数) 字符串(要包括在双引号中) 逻辑值(true或false) 数组(在方括号中) 对象(在花括号中) Json转javascript对象的方法为: eval("(" + str + ")"); 代码示例： <html> <head> <title>Json测试</title> <script src="/Scripts/jquery-1.7.2.min.js" type="text/javascript"></script> <script type="text/javascript"> //基本上，Json返回的要么是对象，要么是数组，如果单纯返回一个字符串，那么就没有必要用Json了，因此 //Json基本就下面这些可，不过要注意双引号 var str0 = "{employees:'测试'}"; var obj0 = eval("(" + str0 +

Json之语法，格式

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adding / dividing / multiplying numbers and operators from array in javascript without eval()

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问题 I'm making a calculator. And the challenge is not to use eval() . I made an array from all the inputs that looks like this: numbers = [1,1,'+',2,'*',3,'-','(',4,'*',5,'+',2,'/',5,')']; Then i convert this array to a string, remove the , and i get a string like this: numberString = "11+2*3-(4*5+2/5)"; So my question is, what is the way to correctly calculate the result of this equation without using eval() ? 回答1: Use an object to map operator strings to functions that implement the operator.

adding / dividing / multiplying numbers and operators from array in javascript without eval()

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Excel VBA evaluate formula from another sheet

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问题 Solved: The problem is in my formula where I'm referencing a cell using INDIRECT() which doesn't work when sheet is different. See answer. I have a formula in one sheet and what I want to do is to use the formula from another sheet, using eval to evaluate the formula. However, the result is not as intended. It seems like the formula is using values at Sheet A instead of the caller Sheet B. Formula in sheet A (See: Screenshot Sheet A) =IF(ISERROR(INDEX('1516Activity'!$B:$B,MATCH(INDIRECT

[翻译]JavaScript秘密花园 - Type Casting,undefined,eval,setTimeout,Auto Semicolon Insertion - 全部完成PDF打包下载

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JavaScript Garden - 原文 JavaScript Garden - 中文翻译 PDF打包下载类型转换 JavaScript 是弱类型语言，所以会在任何可能的情况下应用强制类型转换。 // 下面的比较结果是：truenew Number(10) == 10; // Number.toString() 返回的字符串被再次转换为数字10 == '10'; // 字符串被转换为数字10 == '+10 '; // 同上10 == '010'; // 同上 isNaN(null) == false; // null 被转换为数字 0 // 0 当然不是一个 NaN（译者注：否定之否定）// 下面的比较结果是：false10 == 010;10 == '-10'; ES5 提示: 以 0 开头的数字字面值会被作为八进制数字解析。而在 ECMAScript 5 严格模式下，这个特性被移除了。为了避免上面复杂的强制类型转换，强烈推荐使用严格的等于操作符。虽然这可以避免大部分的问题，但 JavaScript 的弱类型系统仍然会导致一些其它问题。内置类型的构造函数（Constructors of built-in types）内置类型（比如 Number 和 String ）的构造函数在被调用时，使用或者不使用 new 的结果完全不同。 new

基于百度飞浆深度学习框架的各个优化算法比较（手写数字识别）

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# 加载相关库 import os import random import paddle import paddle.fluid as fluid from paddle.fluid.dygraph.nn import Conv2D, Pool2D, FC import numpy as np from PIL import Image import gzip import json 一、数据处理 # 声明数据集文件位置 datafile = './work/mnist.json.gz' print('loading mnist dataset from {} ......'.format(datafile)) # 加载json数据文件 data = json.load(gzip.open(datafile)) print('mnist dataset load done') # 读取到的数据区分训练集，验证集，测试集 train_set, val_set, eval_set = data # 数据集相关参数，图片高度IMG_ROWS, 图片宽度IMG_COLS IMG_ROWS = 28 IMG_COLS = 28 # 打印数据信息 imgs, label = train_set[0], train_set[1] print("训练数据集数量: ", len(imgs)) #

Parsing a string which represents a list of tuples

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问题 I have strings which look like this one: "(8, 12.25), (13, 15), (16.75, 18.5)" and I would like to convert each of them into a python data structure. Preferably a list (or tuple) of tuples containing a pair of float values. I could do that with eval("(8, 12.25), (13, 15), (16.75, 18.5)") which gives me a tuple of tuples, but I don't think naively evaluating external information would be a wise decision. So I wondered what an elegant pythonic solution might look like. 回答1: >>> import ast >>>

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