The Ruby NameError Uninitialized Constant Error

The open-source programming language Ruby is known for its clear syntax and ease of use. That doesnt mean you wont occasionally run into an error message. One of the most vexing is the NameError Uninitialized Constant exception because it has more than one cause. The syntax of the exception follows this format: NameError: uninitialized constant Something or NameError: uninitialized constant Object::Something (where various class names are in place of Something) Ruby NameError Uninitialized Constant Causes The Uninitialized Constant error is a variation of a regular NameError exception class. It has several possible causes.   Youll see this error when the code refers to a class or module that it cant find, often because the code doesnt include require, which instructs the Ruby file to load the class.In Ruby, variables/methods begin with lowercase letters, while classes begin with uppercase letters. If the code doesnt reflect this distinction, youll receive the Uninitialized Constant exception.Still another possible cause for the  NameError  error is that youve made a simple typo in the code.  Ruby is case sensitive, so TestCode and Testcode are completely different.  The code contains mention of rubygems, which is deprecated in all but old versions of Ruby. How to Fix the Error To troubleshoot your code, examine it for the possible causes listed above one at a time. If you find a problem, address it. For example, go through the code looking for a discrepancy in uppercase and lowercase usage on variables and classes.  If you find one and correct it, your problem is probably solved. If it isnt, continue through the other possible causes, fixing as you go. If the class you refer to in the code is in another module, refer to it with its full name like this: #!/usr/bin/env rubymodule MyModule class MyClass; endendc MyModule::MyClass.new About Ruby Exceptions Exceptions are how Ruby draws your attention to problems in the code. When an error in the code is encountered, an  exception is raised or thrown and the program shuts down by default. Ruby publishes an exception hierarchy with predefined classes. NameErrors are in the StandardError class, along with RuntimeError, ThreadError, RangeError, ArgumentError and others. This class includes most of the normal exceptions that you encounter in typical Ruby programs.

A Study On High School - 857 Words

High school was different because I had to adjust to high school, work, and learn to manage money to pay rent and utilities, after my sister and I had left my oldest sister’s house a. I worked at a Mexican restaurant taking orders where White people also worked there, and manage to graduated high school with a full scholarship to cosmetology school, and I worked as a cosmetologist for nine years with my socioeconomic status being low-income, and my social identities of a Mexican female, single parent with two children. I cannot remember how many churches there were, or clubs if any, but I remember going to one the largest Catholic Church in city on holy holidays with my oldest sister and her family, and where White people attended too. After I was out on own, my sister and I would go to church to practice our faith on Sundays and holy days of obligations, and I would also took my children and introduce them to follow my Catholic faith. These experiences taught me about peop le who are different from me, is that they go to school for the same purpose of learning, have the same jobs, and practice the same faith. In my middle adulthood after I married my husband, I moved to Oceanside, California, and after ten years moved to Temecula, California where I presently reside. These communities had better and more jobs, learning facilities, opportunities, and health care. The people within my social sphere where mixture of socioeconomic status, and ethnicities, cultural, andShow MoreRelatedA Study On High School2100 Words   |  9 PagesHigh school senior Timothy Williams woke to the sound of wind scraping the desert sand across a glass pane of his third floor Samarra Hotel room. In the pitch-black room, he rolled over to see the nightstand. A digital clock showed the current time at 9:37AM. Tim thought to himself, Shit! Their buffet breakfast began at nine. They were running late. 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Descarte`s Cartesian Doubt Essay Example For Students

Descarte`s Cartesian Doubt Essay In his first meditation, Descartes sets out with amazing clarity and persistenceto clear himself of every false idea that he has acquired previous to this, anddetermine what he truly knows. To rid him of these rotten apples hehas developed a method of doubt with a goal to construct a set of beliefs onfoundations which are indubitable. On these foundations, Descartes applies threelevels of skepticism, which in turn, generate three levels at which our thoughtsmay be deceived by error. Descartes states quite explicitly in the synopsis,that we can doubt all things which are material as long as we have nofoundations for the sciences other than those which we have had up tillnow(synopsis:12). This skepticism also implies that doubt can free us fromprejudices, enabling the mind to escape the deception of the senses, andpossibly discover a truth which is beyond doubt. The first and main deception inDescartes opinion has evolved from sense perception What ever I have uptill now accepted as mo st true I have acquired either from the senses or throughthe sense. But from time to time I have found that the senses deceive, and it isprudent never to trust completely those who have deceived us evenonce(1:18). At the root of our beliefs, Descartes argues, lie theexperiences we gain from our senses, because these are sometimes mistaken, as inthe case of mirages or objects which appear small in the distance, and becauseof this he will now forfeit all of his most reliable information . Moreimportantly it may be to follow in the steps of Plato and require knowledge thatis certain and absolute ( Prado 1992 ). This argument consists of four mainpremises: 1. All that he has accepted as true up to this point, he has acquiredby the senses or Cartesian Doubt 3 through the senses; 2. but on occasion thesesenses have been deceptive. 3. It is wise not to trust anything that has beendeceiving in the past 4. Therefore, it is possible to be mistaken abouteverything. In premise one his beliefs a re derived from the senses, such as hesees that he has a paper in his hand and concludes that it is a paper, and whatis meant by through the senses, is that his beliefs may have been based onothers sense experience. All Descartes requires for the second premise is thepossibility that he may have been deceived, for if he cannot decide which iswrong, than he must not have any knowledge. This leads to the third premisewhere it seems at least reasonable to assume, that if one has been deceivedpreviously, there is no absolute assurance that it is presently correct. Therefore, there is a chance of being deceived about everything. But manycritics will argue that several of these false percepts can be corrected bymeans of alternative senses, such as he bent stick in water example. Althoughour sight may be tricked into thinking that the mirage exists, by using thesense of touch we can correct this falseness, and uncover what truly exists. Descartes does retreat, and assess the damage from his first level by saying,there are many other beliefs about which doubt is quite impossible, eventhough they are derived from the senses-for example, that I am here, sitting bythe fire, wearing a winter dressing gown.. (1:18). Here even heobjects to the validity of his argument, even if he could be deceived aboutanything he perceives, this does not mean that he is deceived about everything. Just because his senses are unreliable at times is not proof enough thateverything in the world is false (Williams 1991). In addition to beingdelusional, Descartes believes we can be tricked by madness or insanity. Sincethose who are insane may interpret things detached from reality by means oftheir senses, how could it be denied that these hands or this whole bodyare mine? Unless perhaps I were to liken myself to madmen, whose brains are sodamaged by the persistent vapours of melancholia (1:19 ), they in factbelieve these percepts to be true. Though Descartes does go on to say suchpeople are insane, and I would be thought equally mad if I took anything fromthem as a model for myself, and continues by likening the dreams he has tothe experiences a madman faces when awake. From here Descartes makes a strongerargument for calling into question his common sense beliefs, the possibilitythat he might be dreaming, that every emotion and every sense perception appearsto him only in a dream . Since there is always a possibility that we may in factbe dreaming, this hypothesis is done to provoke his faith in reality and thesenses, to get the absolute certainty of how things may appear or feel (Prado1992). His view on this is taken from the fact that when dreaming, the sametypes of mental states and feelings are present as when we are awake, Howoften, asleep at night , I am convinced of just such a familiar event-that I amhere in my dressing-gown, sitting by the fire- when in fact I am lying undressedin bed (1:19). Since there is no absolute way in determining thewaking state from the dreaming state, when it comes to sense experience, we areno better off awake than asleep. Therefore our judgment must be suspended evenwhen we are sure that our state is that of waking because we clearly haveno reason to believe that effects resemble their causes in the waking state,since they clearly do not in the dreaming state (Prado, 1992). The onlyway we can avoid the suspension of judg ement is only if we have a standard todetermine where the truth exists (Williams 1986). To use the conflict of thestick being bent in water, what sense is it that we should believe, when we haveno tool to decipher the truth? Thus, the suspension of truth works for the doubtof he senses as well. The reason why doubting the senses is not enough to basean entirely new set of ideas, is due to the fact that it does not call intoquestion all of ones common sense beliefs, for the representations found indreams are derived from real objects, although possibly arranged in a differentway. The thoughts and feelings of a dream are real, they are the same thoughtsand feelings that occur every day in the waking state. To be afraid during adream is the same feeling experienced if . It is due to the similarities infeelings and thought between dreaming and waking, that Descartes is able to findground for doubt, there are never any sure signs by means of which beingawake can be distinguished from bei ng asleep (1:19). This than leadsto the eternal skeptical question : How can I tell whether at this momentI am awake or asleep? (Malcolm, 1967). If we take any series of thoughts,emotions or feelings, it is possible that the same series can occur whiledreaming or awake. Thus, we can never be absolutely clear on whether what we areexperiencing at that exact moment in time is a dream, or that of a waking state. Though Prado (1992) insists that Descartes states in the sixth meditation, thattemporal coherence allows us to decipher between the waking and dreaming states. The aim here then would be to prove that there is nothing in the waking state toconfirm the accuracy of sense experience. The fact that at any given moment ourcurrent state could change drastically and render the previous state anillusion, may be enough to support his skeptical nature on thus, his CartesianDoubt 6 second level of doubt (Williams 1991). As long as Descartes second levelof doubt is accepted, we are able to continue on to his third level of doubt, orwhat is known as hyperbolical doubt. Descartes considers our beliefs withindreams when he says that some beliefs remain indubitable while others are sweptaway by imagination. Such things as the laws of physics can be broken withindreams, where other concepts such as arithmetic or geometry remain unchanged:physics, astronomy, medicine and all other disciplines which depend on the studyof composite things, are doubtful; while arithmetic, geometry ans other subjectsof this kind, which deal only with the simplest and most genera l things,regardless of whether they really exist in nature or not, contain somethingcertain and indubitable. (1:20) He decides that certain things which areaccepted universally, such as mathematics, are irrefutable. The dream hypothesisis not enough to doubt such things as mathematics, as we may be dreaming thatthere appears a square in front of us, but we cannot doubt our reason, such thatit has four sides, or that there is only one square that we see and not two orthree. He moves on to discuss the origins of our beliefs, and the role of anomnipotent God. He believes that there is a God, due to the fact that this ideaof God is firmly rooted in his mind, and he also believes that thisomnipotent God would not deceive him since he is supremely good. Heexamines the assumption that God is perfect and omnipotent, and therefore thesource for all of our thoughts and ideas. Since Descartes is abandoning all ofhis old beliefs, this would suggest that God tried to deceive him. He wonderswhy s uch a perfect God would deceive him, and figures it must be doubtful. Homophobia and Hate Crimes as a Result EssayCartesian Doubt 7 Now Descartes imagines that God is not the one who isdeceiving him, but none other than a malevolent demon, who with deceitful power,implants false beliefs, I will suppose therefore that not God, who issupremely good and the source of truth, but rather some malicious demon of theutmost power and cunning has employed all his energies in order to deceiveme (1:22). When determining what is open to doubt, Descartes evildemon hypothesis conveniently creates a being who is omnipotent and who uses thepower solely to deceive. What Descartes achieves is making problematic a host ofideas he entertains as products of reason , opposed to products of the senses,which the dream hypothesis takes care of (Prado 1992). Although L.G. Miller(1992) suggests that the propositions of mathematics survive the perception anddream arguments, but only to be unsettled by the deceiver God hypothesis,Could not an all-powerful demon make me believe t hose propositions aretrue when, as a matter of fact, they are not? The deceiver God does notsucceed if the person accepts that the reality he lives in is true. However,with the rise of skepticism and questioning the veracity of whether the world welive in is accurate or not, perhaps the demon has won after all. Descartes thenleaves the first meditation in a state of confusion. He knows at least howthings seem to appear to him, even if he has no idea how they really are Iam like a prisoner who is enjoying an imaginary freedom while asleep, he dreadsbeing woken up, and goes along with the pleasant as long as hecan(1:23[15). Descartes clearly refocused metaphysical thinking into thephysical world, by turning it toward the natural world. His basic structure hasfour uses of doubt, firstly to free us from preconceived opinions or prejudice,the second is to lead the mind away from the senses, the Cartesian Doubt 8 thirduse of doubt makes it impossible to have any further doubts about those thingswhich alter such an extensive doubt and are discovered to be true,while the fourth is to provide us with an understanding of what certainty is. Descartes methodological doubt can be defined as foundationalism, which is thebelief that knowledge is formed on different levels, much like an invertedpyramid. Such that, complex beliefs come first, then beneath that are simplerbeliefs and beneath them are the simplest beliefs. Foundationalism requires notonly this hierarchy effect, but also that nothing is accepted as knowledge untilwe know upon what it is based (Prado 1992). In summary of what the three mainarguments undermine, the argument from the illusion or deceptiveness of thesenses undermines ordinary sense perception. Undermining ordinary senseperception and scientific observation as well as the more theoretical parts ofthe physical sciences and hence these sciences as a whole is the dreamhypothesis, while the deceiver God hypothesis undermines the pure mathematicalsciences such as arithmetic and geometry. Descartes metaphysical doubtemphasizes purging the old falsehoods and buildings up again from the bedrock ofthe indubit able of our existence as thinkers. Whether or not the extensivenessof such skepticism used by Descartes is necessary, remains open for doubt. Butfor one to gain any knowledge what so ever, they must be capable of doubting atsome point or another, rather than accepting all that they may hear. It would beextremely credulous and naive to never doubt or question it is only natural todoubt and challenge that which one does not believe, and to a certain extent,being the natural extent, it is useful and necessary, When Descartesbegins to doubt in an epistemological mode, he cannot stop short of doubtingwhether Cartesian Doubt 9 he himself exists as a doubter (Prado 1992).. Perhaps, when the poet Charles Bukowski said the more crap you believe,the better off you are, he realized that such an extensive doubt can beharmful to the majority of people, because they are in fact betteroff believing in their senses, their God, and their ability to determinewhether they are sleeping or awake. It is possible that it may be beneficial tolive and die being deceived, and be ignorant to that deception, than to live anddie searching for truth where truth may not be found, for the true determinantto whether such an extensive skepticism is beneficial or necessary depends onthe individual. Neither Descartes nor Bukowski can speak for anyone other thanthemselves.

The inclined plane Essay Example

The inclined plane Paper If the metal trolley is let free down the inclined plane, its move will be accelerated. Later, as the air resistance and friction force have influence on acceleration, they will change it.  Analysis:  The first part of experiment included preparing an inclined plane. The physics book by Giancoli was laying down on one table, while the other school table was laid on the book. This action is presented on the Drawing 1. The length of the school table is 120 1 cm measured by a ruler. The width of the table is not required. The difference in levels between a table and the highest point of the inclined plane is 6.8 cm . Using a ruler with exactness to millimeters and a chalk, we calculated and determined six distances of the same value 15 cm with the uncertainty of 1 cm. Next we checked if the stopwatch worked properly and checked the trolley. Its size is 191 cm; its mass is not relevant.  The most important part of the experiment included precise measurements. In order to do that, we repeated measurements of distance and time the trolley needed to travel given distance. Each measurement took place 10 times. Six distances measured ten times gave a total amount of sixty measurements. Using 10 measurements we calculate the average time taken to travel given distance. We added all ten measurements of time for each distance and divided by ten. The results can be seen in the Table. We will write a custom essay sample on The inclined plane specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on The inclined plane specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on The inclined plane specifically for you FOR ONLY $16.38 $13.9/page Hire Writer Then, the equation V=d/t was used. The velocity was calculated and so was the change of time and the change of velocity. Then all results were recorded in Table 3 Later on, a=?V/?t was used. The acceleration for each time was calculated and recorded in Table 3. Another step was to calculate the uncertainty of the acceleration using the equation: ?a/a= ?v/v+?t/t. The time, the velocity and the acceleration from the Table 3 were used and the results were recorded in Table 3. The uncertainty of the distance is 1 centimeter and is constant; the uncertainty of time is 0.05 second and also is constant. The uncertainty of velocity and acceleration is not constant. After recording all necessary datas, the averages of time, velocity, acceleration and uncertainty were calculated- the measurements of each six distances were added and divided by number of the measurements-six. All measurements were rounded to second decimal place.  The next step to measure the acceleration was constructing the graph showing the distance dependence on time (Graph 1). The best-fit line was drawn, so were the line of maximal slope and the line of minimal slope. Then, the Graph 2 showing the average acceleration dependence on time was constructed. The best fit line was drawn. Last step was creating a Graph 3 representing the relationship between given velocities. velocity In the experiment, the values of air resistance and friction force were neglected, but the air resistance and friction force has influenced the whole experiment.  The constructed graphs prove the hypothesis incorrect. The line touches all error bars, so it means there is a relationship between the linear quantities. The unit of the uncertainty of the distance is expressed in centimeters, the uncertainty of time in seconds and the uncertainty of acceleration in centimeters per second square. The air force and friction has a significant influence on the value of acceleration during the experiment. The conclusions are reasonable. In the experiment there was error due to the lack of precision of the ruler. Its not possible to be precise using the standard ruler measuring with precision to millimeters. Another possible error can be present due to the inability to see and mark the exact point where the identical distances were. Error also came from inability to know exactly when to stop the timer; also the additional seconds-reaction time of the experimentator. Given errors could cause further errors in calculations of accelerations. All errors have reasonable values. The values of the measurements are similar to each other. The number of repetition is proper. The fact that the graph doesnt go through the point (0,0) shows presence of the systematic error. As the exact value of air resistance and friction forces were not regarded, the error could occur. There also could be the error due to the slight change of levels because of soft cover of Giancoli.  As all experiments, this one also involve errors and can be improved. The uncertainty could be reduced, the millimeter paper could be used instead of the ruler, hard cover instead of Giancoli. Considering air resistance and friction force could help with estimating particulars. The usage of more precise timer could also improve our measurements and further analysis. More readings could give better results and therefore improve the whole experiment. The fact that the inclined plane had a low angle could also change the expected results; if the inclined plane were higher, the results would be more precise.  Not including and using in calculations the values of air resistance and friction force has influenced the calculation, and what follows, the results of the experiment. If the values of air resistance, fraction force and other variables were considered and therefore calculated, it would show, that our experiment was done correctly.