eval

问题 The below piece of code is aimed at converting a factorial into its products. E.g. "4!" --> "(4*3*2*1)" . This code does not work due to the line exec(codeToRun) . However, if I instead put the value of codeToRun in place of exec(codeToRun) then it works perfectly so why doesn't exec work? Doesn't work ↓ def checkSpecialChars(char, stringToCheck, codeToRun): while char in stringToCheck: currentString="" for i in range(len(stringToCheck)): if stringToCheck[i]==char: try: eval(codeToRun) except

问题 I have a template filed as listed below. I need to display millisecond part of DateTime also. I have read about the dateValue.ToString("fff") format in http://msdn.microsoft.com/en-us/library/bb882581.aspx How to: Display Milliseconds in Date and Time Values . What is the best way to display it in Template Field with Eval? CODE <asp:TemplateField HeaderText="Event Time"> <ItemTemplate> <asp:Literal ID="ltlTime" runat="server" Text='<%# Eval("LastChangeTime") %>' ></asp:Literal> <asp

问题 I am trying to make a method that takes a string formula, and solves the integral of that formula by doing a Riemann's sum with very small intervals. I am using the ScriptEngine and ScriptEngineManager classes to evaluate the function (with the eval() method). For some reason, I am getting this error: Exception in thread "main" java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Double at sum.integral(sum.java:31) at sum.main(sum.java:13) import java.beans.Expression;

问题 Javax ScriptEngine and JEval works similarly, you input an string and send it to be evaluated, and it will return you the result of it: In ScriptEngine (almost the same in JEval): System.out.println(engine.eval("2*3+4")); will result in: 10.0 But when I try to make it an exponential: System.out.println(engine.eval("2^3+4")); will result in: 5.0 But it really should result in 12 (2^3 = 8, 8+4=12), so my question is how can I set it up in a way that the string which the will be all the whole

问题 i tried googling but didnt get a very specific answer.. then again, i might be not using the right keywords.. can someone point out the "security" issues javascript eval can cause? with examples with be very nice. will also do if you can point to an existing web resource which does the same. Edit : I only need the security implications for eval. 回答1: eval() may be a sign of poor design. For instance, sometimes people use it to access object properties because they don't know you can use the [

问题 Why doesn't the subroutine with try/catch give me the same results as the eval-version does? #!/usr/bin/env perl use warnings; use strict; use 5.012; use Try::Tiny; sub shell_command_1 { my $command = shift; my $timeout_alarm = shift; my @array; eval { local $SIG{ALRM} = sub { die "timeout '$command'\n" }; alarm $timeout_alarm; @array = qx( $command ); alarm 0; }; die $@ if $@ && $@ ne "timeout '$command'\n"; warn $@ if $@ && $@ eq "timeout '$command'\n"; return @array; } shell_command_1(

问题 $arr = eval("array('foo'=>'bar');"); // returns null var_dump($arr); Can someone please explain why did I get null instead of an array? 回答1: You need to return the array. From the docs: eval() returns NULL unless return is called in the evaluated code, in which case the value passed to return is returned. So you need to do: $arr = eval("return array('foo'=>'bar');"); 回答2: Did you mean eval("\$arr = array('foo'=>'bar');"); var_dump($arr); 回答3: The eval function executes the php code given to

问题 Suppose I have a file example.py : import example VVV = 2 DictionaryNameB = { 'a' : VVV, 'bb' : 'SomethingB', 'c' : False, 'ccc' : None, 'dddd' : 'true', 'eeeee' : 0.123456, 'f' : 2, 'h' : [1,2,3] } I wrote a function that uses ast.literal_eval() : def getDicFromFile(self, dic_name): with open( 'example.py' ) as f: file_data = f.read() match = re.findall('%s[^{]+\{[^\}]+\}' % dic_name, file_data, re.MULTILINE)[0] # print(match) dicObject = ast.literal_eval(match[len(dic_name)+3:]) return

问题 How do you write a function in bash that executes the command that it is given as an argument, where The given command may be an alias Arguments must be passed on exactly as given; no evaluating may be done In other words, how to write an as-transparent-as-possible wrapper function. The goal of the wrapper function could for example be to set the current directory before and after the given command, and/or set environment variables, or time how long the given command takes,... As a simple

问题 I have a few arrays with like names. ArrayTop[] ArrayLeft[] ArrayRight[] ArrayWidth[] I am trying to set the name dynamically in a function and then set value. I have tried many ways of dynamically picking the right array but have not come up with a solution. function setarray(a,b,c){ eval(Array+a+[b])=c } setarray('Top',5,100) In this example i am trying to set. ArrayTop[5]=100 回答1: If you are doing this in the browser, one possible solution would be to do: function setArray(a, b, c){ window