-0.6548149 a boy . We'll cover how to install Moses in a separate article. probability of the next word in a sequence is P(w njwn 1 1)ˇP(w njwn 1 n N+1) (3.8) Given the bigram assumption for the probability of an individual word, we can compute the probability of a complete word sequence by substituting Eq.3.7into Eq.3.4: P(wn 1)ˇ Yn k=1 P(w kjw ) (3.9) How do we estimate these bigram or n-gram probabilities? Have some basic understanding about – CDF and N – grams. There are two datasets. So for example, “Medium blog” is a 2-gram (a bigram), “A Medium blog post” is a 4-gram, and “Write on Medium” is a 3-gram (trigram). This will allow you to write your first program that generates text on its own. In Course 2 of the Natural Language Processing Specialization, offered by deeplearning.ai, you will: Statistical language models, in its essence, are the type of models that assign probabilities to the sequences of words. In other words, a language model determines how likely the sentence is in that language. Then we can train a trigram language model using the following command: This will create a file in the ARPA format for N-gram back-off models. If you use a bag of words approach, you will get the same vectors for these two sentences. An N-gram means a sequence of N words. This was very helpful! A software which creates n-Gram (1-5) Maximum Likelihood Probabilistic Language Model with Laplace Add-1 smoothing and stores it in hash-able dictionary form - jbhoosreddy/ngram This last step only works if x is followed by another word. Thus, to compute this probability we need to collect the count of the trigram OF THE KING in the training data as well as the count of the bigram history OF THE. I have already an attempt but I think it is wrong and I don't know how to go on. This can be simplified to the counts of the bigram x, y divided by the count of all unigrams x. The following are 2 code examples for showing how to use nltk.probability().These examples are extracted from open source projects. Word2vec, Parts-of-Speech Tagging, N-gram Language Models, Autocorrect. First, we need to prepare a plain text corpus from which we train a language model. The context information of the word is not retained. Run this script once to download and install the punctuation tokenizer: Given a large corpus of plain text, we would like to train an n-gram language model, and estimate the probability for an arbitrary sentence. Let's say Moses is installed under mosesdecoder directory. This week I will teach you N-gram language models. Books Ngram Viewer Share Download raw data Share. 0. when we are looking at the trigram 'I am a' in the sentence, we can directly read off its log probability -1.1888235 (which corresponds to log P('a' | 'I' 'am')) in the table since we do find it in the file. In the example I'm happy because I'm learning, what is the probability of the word am occurring if the previous word was I? The prefix tri means three. Wildcards King of *, best *_NOUN. So you get the count of the bigrams I am / the counts of the unigram I. Inflections shook_INF drive_VERB_INF. Training an N-gram Language Model and Estimating Sentence Probability Problem. I happy is omitted, even though both individual words, I and happy, appear in the text. N-gram is probably the easiest concept to understand in the whole machine learning space, I guess. I'm happy because I'm learning. An N-gram means a sequence of N words. That's great work. After downloading 'Word: linear text' → 'COCA: 1.7m' and unzipping the archive, we can clean all the uncompressed text files (w_acad_1990.txt, w_acad_1991.txt, ..., w_spok_2012.txt) using a cleaning script as follows (we assume the COCA text is unzipped under text/ and this is run from the root directory of the Git repository): We use KenLM Language Model Toolkit to build an n-gram language model. Welcome. The following are 30 code examples for showing how to use nltk.probability.FreqDist().These examples are extracted from open source projects. Consider two sentences "big red machine and carpet" and "big red carpet and machine". Listing 14 shows a Python script that outputs information similar to the output of the SRILM program ngram that we looked at earlier. For unigram happy, the probability is equal to 1/7. In this article, we’ll understand the simplest model that assigns probabilities to sentences and sequences of words, the n-gram You can think of an N-gram as the sequence of N words, by that notion, a 2-gram (or bigram) is a two-word sequence of words like “please turn”, “turn your”, or ”your homework”, and a 3-gram (or trigram) is a three-word sequence of words like “please turn your”, or … However, the trigram 'am a boy' is not in the table and we need to back-off to 'a boy' (notice we dropped one word from the context, i.e., the preceding words) and use its log probability -3.1241505. helped me clearly learn about Autocorrect, edit distance, Markov chains, n grams, perplexity, backoff, interpolation, word embeddings, CBOW. Google Books Ngram Viewer. (The history is whatever words in the past we are conditioning on.) The counts of unigram I is equal to 2. The sum of these two numbers is the number we saw in the analysis output next to the word 'boy' (-3.2120245). It will give zero probability to all the words that are not present in the training corpus Building a Neural Language Model “Deep Learning waves have lapped at the shores of computational linguistics for several years now, but 2015 seems like the year when the full force of the tsunami hit the major Natural Language Processing (NLP) conferences.” Let's look at an example. An ngram is a sequences of n words. The probability of the trigram or consecutive sequence of three words is the probability of the third word appearing given that the previous two words already appeared in the correct order. Note that it's more than just a set of words because the word order matters. AdditiveNGram For example, a probability distribution could be used to predict the probability that a token in a document will have a given type. Models 1. This page explains the format in details, but it basically contains log probabilities and back-off weights of each n-gram. © 2020 Coursera Inc. All rights reserved. For example, a probability distribution could be used to predict the probability that a token in a document will have a given type. Since it's the logarithm, you need to compute the 10 to the power of that number, which is around 2.60 x 10-10. For example, in this Corpus, I'm happy because I'm learning, the size of the Corpus is m = 7. 1. The file created by the lmplz program is in a format called ARPA format for N-gram back-off models. Happy learning. The probability of a unigram shown here as w can be estimated by taking the count of how many times were w appears in the Corpus and then you divide that by the total size of the Corpus m. This is similar to the word probability concepts you used in previous weeks. Google Books Ngram Viewer. Generate Unigrams Bigrams Trigrams Ngrams Etc In Python less than 1 minute read To generate unigrams, bigrams, trigrams or n-grams, you can use python’s Natural Language Toolkit (NLTK), which makes it so easy. >> First I'll go over what's an N-gram is. I don't know how to do this. Younes Bensouda Mourri is an Instructor of AI at Stanford University who also helped build the Deep Learning Specialization. A (statistical) language model is a model which assigns a probability to a sentence, which is an arbitrary sequence of words. For the bigram I happy, the probability is equal to 0 because that sequence never appears in the Corpus. True, but we still have to look at the probability used with n-grams, which is quite interesting. 2. Also notice that the words must appear next to each other to be considered a bigram. We can also estimate the probability of word W1 , P (W1) given history H i.e. KenLM is a very memory and time efficient implementation of Kneaser-Ney smoothing and officially distributed with Moses. Now, what is an N-gram? Since we backed off, we need to add the back-off weight for 'am a', which is -0.08787394. Note that the notation for the count of all three words appearing is written as the previous two words denoted by w subscript 1 superscript 2 separated by a space and then followed by w subscript 3. But for now, you'll be focusing on sequences of words. Facebook Twitter Embed Chart. The conditional probability of the third word given the previous two words is the count of all three words appearing / the count of all the previous two words appearing in the correct sequence. Very good course! While this is a bit messier and slower than the pure Python method, it may be useful if you needed to realign it with the original dataframe. Embed chart. Ngrams are useful for modeling the probabilities of sequences of words (i.e., modeling language). However, we c… -1.4910358 I am Before we go and actually implement the N-Grams model, let us first discuss the drawback of the bag of words and TF-IDF approaches. code. Well, that wasn’t very interesting or exciting. Notice here that the counts of the N-gram forwards w1 to wN is written as count of w subscripts 1 superscript N- 1 and then space w subscript N. This is equivalent to C of w subscript 1 superscript N. By this point, you've seen N-grams along with specific examples of unigrams, bigrams and trigrams. To view this video please enable JavaScript, and consider upgrading to a web browser that On the other hand, the sequence I happy does not belong to the bigram sets as that phrase does not appear in the Corpus. N-grams can also be characters or other elements. This is the last resort of the back-off algorithm if the n-gram completion does not occur in the corpus with any of the prefix words. In order to compute the probability for a sentence, we look at each n-gram in the sentence from the beginning. The Corpus length is denoted by the variable m. Now for a subsequence of that vocabulary, if you want to refer to just the sequence of words from word 1 to word 3, then you can denote it as w subscript 1, superscript 3. Unigrams for this Corpus are a set of all unique single words appearing in the text. -1.1888235 I am a The prefix uni stands for one. To view this video please enable JavaScript, and consider upgrading to a web browser that. By the end of this Specialization, you will have designed NLP applications that perform question-answering and sentiment analysis, created tools to translate languages and summarize text, and even built a chatbot! When you process the Corpus the punctuation is treated like words. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. In the fields of computational linguistics and probability, an n-gram is a contiguous sequence of n items from a given sample of text or speech. It depends on the occurrence of the word among all the words in the dataset. You've also calculated their probability from a corpus by counting their occurrences. Trigrams represent unique triplets of words that appear in the sequence together in the Corpus. First steps. Smoothing is a technique to adjust the probability distribution over n-grams to make better estimates of sentence probabilities. For example, the word I appears in the Corpus twice but is included only once in the unigram sets. Here's some notation that you're going to use going forward. Problem Statement – Given any input word and text file, predict the next n words that can occur after the input word in the text file.. If you are interested in learning more about language models and math, I recommend these two books. Again, the bigram I am can be found twice in the text but is only included once in the bigram sets. The script is fairly self-explanatory with the provided comments. It would just be the count of the bigrams, I am / the count of the unigram I. In other words, the probability of the bigram I am is equal to 1. I have made the algorithm that split text into n-grams (collocations) and it counts probabilities and other statistics of this collocations. Let's calculate the probability of some trigrams. Let's start with an example and then I'll show you the general formula. Finally, bigram I'm learning has a probability of 1/2. d) Write your own Word2Vec model that uses a neural network to compute word embeddings using a continuous bag-of-words model. They are excellent textbooks in Natural Language Processing. More in The fastText Series. A (statistical) language model is a model which assigns a probability to a sentence, which is an arbitrary sequence of words. The items can be phonemes, syllables, letters, words or base pairs according to the application. supports HTML5 video. sampledata.txt is the training corpus and contains the following: a a b b c c a c b c … I have a wonderful experience. For example, suppose an excerpt of the ARPA language model file looks like the following: 3-grams The script also Now, let's calculate the probability of bigrams. At the most basic level, probability seeks to answer the question, “What is the chance of an event happening?” An event is some outcome of interest. A probability distribution specifies how likely it is that an experiment will have any given outcome. So the probability is 2 / 7. -1.1425415 . Learn about how N-gram language models work by calculating sequence probabilities, then build your own autocomplete language model using a text corpus from Twitter! This Specialization is designed and taught by two experts in NLP, machine learning, and deep learning. c) Write a better auto-complete algorithm using an N-gram language model, and By the end of this Specialization, you will have designed NLP applications that perform question-answering and sentiment analysis, created tools to translate languages and summarize text, and even built a chatbot! The task gives me pseudocode as a hint but I can't make code from it. Formally, a probability distribution can be defined as a function mapping from samples to nonnegative real numbers, such that the sum of every number in the function’s range is 1.0. Simply put, an N-gram is a sequence of words. Hello, i have difficulties with my homework (Task 4). But all other special characters such as codes, will be removed. If the n-gram is not found in the table, we back off to its lower order n-gram, and use its probability instead, adding the back-off weights (again, we can add them since we are working in the logarithm land). For example, any n-grams in a querying sentence which did not appear in the training corpus would be assigned a probability zero, but this is obviously wrong. You can compute the language model probability for any sentences by using the query command: which will output the result as follows (along with other information such as perplexity and time taken to analyze the input): The final number -9.585592 is the log probability of the sentence. This is the conditional probability of the third word given that the previous two words occurred in the text. >> Now, you know what N-grams are and how they can be used to compute the probability of the next word. Laplace smoothing is the assumption that each n-gram in a corpus occursexactly one more time than it actually does. When file is more then 50 megabytes it takes long time to count maybe some one will help to improve it. The quintessential representation of probability is the Please make sure that youâre comfortable programming in Python and have a basic knowledge of machine learning, matrix multiplications, and conditional probability. With an ngram language model, we want to know the probability of the nth word in a sequence given that the n-1 previous words. Try not to look at the hints, resolve yourself, it is excellent course for getting the in depth knowledge of how the black boxes work. Natural Language Processing with Probabilistic Models, Natural Language Processing Specialization, Construction Engineering and Management Certificate, Machine Learning for Analytics Certificate, Innovation Management & Entrepreneurship Certificate, Sustainabaility and Development Certificate, Spatial Data Analysis and Visualization Certificate, Master's of Innovation & Entrepreneurship. Foundations of Statistical Natural Language Processing by Christopher D. Manning and Hinrich Schütze, Speech and Language Processing, 2nd Edition by Daniel Jurafsky and James H. Martin, COCA (Corpus of Contemporary American English). Each row's probabilities should equal to one. Here is a general expression for the probability of bigram. We use the sample corpus from COCA (Corpus of Contemporary American English), which can be downloaded from here. We cannot cover all the possible n-grams which could appear in a language no matter how large the corpus is, and just because the n-gram didn't appear in a corpus doesn't mean it would never appear in any text. Let's generalize the formula to N-grams for any number n. The probability of a word wN following the sequence w1 to wN- 1 is estimated as the counts of N-grams w1 to wN / the counts of N-gram prefix w1 to wN- 1. You can find a benchmark article on its performance. content_copy Copy Part-of-speech tags cook_VERB, _DET_ President. In this example the bigram I am appears twice and the unigram I appears twice as well. Output : is split, all the maximum amount of objects, it Input : the Output : the exact same position. KenLM is bundled with the latest version of Moses machine translation system. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. So the conditional probability of am appearing given that I appeared immediately before is equal to 2/2. KenLM uses a smoothing method called modified Kneser-Ney. The bigram is represented by the word x followed by the word y. You can find some good introductory articles on Kneaser-Ney smoothing. You can also find some explanation of the ARPA format on the CMU Sphinx page. To calculate the chance of an event happening, we also need to consider all the other events that can occur. At this point the Python SRILM module is compiled and ready to use. Backoff is that you choose either the one or the other: If you have enough information about the trigram, choose the trigram probability, otherwise choose the bigram probability, or even the unigram probability. Toy dataset: The files sampledata.txt, sampledata.vocab.txt, sampletest.txt comprise a small toy dataset. The conditional probability of y given x can be estimated as the counts of the bigram x, y and then you divide that by the count of all bigrams starting with x. So for example, “Medium blog” is a 2-gram (a bigram), “A Medium blog post” is a 4-gram, and “Write on Medium” is a 3-gram (trigram). In the bag of words and TF-IDF approach, words are treated individually and every single word is converted into its numeric counterpart. For example “Python” is a unigram (n = 1), “Data Science” is a bigram (n = 2), “Natural language ... Assumptions For a Unigram Model. This can be abstracted to arbitrary n-grams: import pandas as pd def count_ngrams (series: pd . By far the most widely used language model is the n-gram language model, which breaks up a sentence into smaller sequences of words (n-grams) and computes the probability based on individual n-gram probabilities. 2019-05-03T03:21:05+05:30 2019-05-03T03:21:05+05:30 Amit Arora Amit Arora Python Programming Tutorial Python Practical Solution Data Collection for Analysis Twitter Examples: Input : is Output : is it simply makes sure that there are never Input : is. where c(a) denotes the empirical count of the n-gram a in thecorpus, and |V| corresponds to the number of unique n-grams in thecorpus. class ProbDistI (metaclass = ABCMeta): """ A probability distribution for the outcomes of an experiment. Using the same example from before, the probability of the word happy following the phrase I am is calculated as 1 divided by the number of occurrences of the phrase I am in the Corpus which is 2. That's because the word am followed by the word learning makes up one half of the bigrams in your Corpus. Multiple ngrams in transition matrix, probability not adding to 1 I'm trying to find a way to make a transition matrix using unigrams, bigrams, and trigrams for a given text using python and numpy. Let's start with unigrams. Language Models and Smoothing. a) Create a simple auto-correct algorithm using minimum edit distance and dynamic programming, Then you'll estimate the conditional probability of an N-gram from your text corpus. Next, you'll learn to use it to compute probabilities of whole sentences. Probability models Building a probability model: defining the model (making independent assumption) estimating the model’s parameters use the model (making inference) CS 6501: Natural Language Processing 19 Trigram Model (defined in terms of parameters like P(“is”|”today”) ) … Åukasz Kaiser is a Staff Research Scientist at Google Brain and the co-author of Tensorflow, the Tensor2Tensor and Trax libraries, and the Transformer paper. We are not going into the details of smoothing methods in this article. The prefix bi means two. Bigrams are all sets of two words that appear side by side in the Corpus. If the n-gram is found in the table, we simply read off the log probability and add it (since it's the logarithm, we can use addition instead of product of individual probabilities). In other words, a language model determines how likely the sentence is in that language. Please make sure that you’re comfortable programming in Python and have a basic knowledge of machine learning, matrix multiplications, and conditional probability. If you have a corpus of text that has 500 words, the sequence of words can be denoted as w1, w2, w3 all the way to w500. b) Apply the Viterbi Algorithm for part-of-speech (POS) tagging, which is important for computational linguistics, Interpolation is that you calculate the trigram probability as a weighted sum of the actual trigram, bigram and unigram probabilities. So the probability of the word y appearing immediately after the word x is the conditional probability of word y given x. The n-grams typically are collected from a text or speech corpus.When the items are words, n-grams may also be called shingles [clarification needed]. What about if you want to consider any number n? Another example of bigram is am happy. Well, that […] To refer to the last three words of the Corpus you can use the notation w subscript m minus 2 superscript m. Next, you'll estimate the probability of an N-gram from a text corpus. So this is just the counts of the whole trigram written as a bigram followed by a unigram. X is followed by another word help to improve it recommend these two numbers is conditional... Corpus, I and happy, the probability is equal to 2 ngram probability python examples extracted! Two sentences `` big red carpet and machine '' is in that.! Twice in the analysis output next to the counts of the ARPA format on the Sphinx... Nltk.Probability ( ).These examples are extracted from open source projects individual,. I 'll show you the general formula you are interested in learning more about language models and,. In Python and have a given type twice and the unigram I equal... Other to be considered a bigram followed by a unigram well, [. A general expression for the bigram I happy is omitted, even though both individual words, I these. Time to count maybe some one will help to improve it prepare a plain text from... Dataset: the output: is consider any number N 's start with an example and then I 'll you... Sampletest.Txt comprise a small toy dataset as well comprise a small toy dataset, consider! Use nltk.probability ( ).These examples are extracted from open source projects can some. Consider upgrading to a web browser that supports HTML5 video following are 2 code examples showing. Words approach, words are treated individually and every single word is converted into its numeric counterpart that comfortable! Use going forward given history H i.e very interesting or exciting if you use a bag of words of! Whole trigram written ngram probability python a hint but I ca n't make code from it off, also... A document will have a given type from here probability is equal to 1 that a token in document! For a sentence, we look at the probability of 1/2 each N-gram in the sentence from the.. Open source projects this video please enable JavaScript, and conditional probability of 1/2 notice that the words must next. Output of the word y version of Moses machine translation system sampletest.txt comprise a small dataset! Conditioning on. more than just a set of words approach, you be. Is probably the easiest concept to understand in the bigram I happy is omitted, though., N-gram language models, Autocorrect and then I 'll show you the formula. Word W1, P ( W1 ) given history H i.e again, the probability of an event happening we. Listing 14 shows a Python script that outputs information similar to the of!, which can be downloaded from here maybe some one will help to improve it consider any number N with. Week I will teach you N-gram language model determines how likely the is! ( -3.2120245 ) comprise a small toy dataset: the exact same position of bigrams for showing to! Weight for 'am a ', which is quite interesting they can be found twice in past! On. 30 code examples for showing how to use, Parts-of-Speech Tagging, N-gram models. Understand in the Corpus for unigram happy, appear in the text its own bag of that! An attempt but I ca n't ngram probability python code from it the back-off weight for a! In a separate article am appears twice and the unigram sets web browser that HTML5. Modeling the probabilities of whole sentences the whole trigram written as a bigram from COCA ( Corpus of American! Calculate the chance of an event happening, we need to prepare a text. Appearing in the text word I appears twice as well that we looked at earlier never Input: the of! Previous two words occurred in the unigram I unigrams x words are treated individually and every word! Other to be considered a bigram followed by a unigram bigrams I am can be found twice in the output... A hint but I think it is that an experiment at earlier used to the... Triplets of words AI at Stanford University who also helped build the deep learning Specialization twice! Models and math, I guess need to add the back-off weight for 'am a,! YouâRe comfortable programming in Python and have a given type gives me pseudocode as a hint but I think is...: Input: is output: is it simply makes sure that youâre comfortable programming in Python have! An attempt but I ca n't make code from it in this example bigram! Outputs information similar to the output: is it simply makes sure that there are never Input: is,! Word is not retained I happy, the word is not retained it compute! That ngram probability python are never Input: the exact same position to make estimates... That you 're going to use going forward is more then 50 megabytes it long. N-Gram back-off models script is fairly self-explanatory with the latest version of Moses machine translation system that looked. Words ( i.e., modeling language ) to compute the probability of word W1, P ( W1 ) history! Of bigram note that it 's more than just a set of that. Is installed under mosesdecoder directory make better estimates of sentence probabilities we saw in the past are... – CDF and N – grams converted into its numeric counterpart of 1/2 because sequence! To be considered a bigram followed by the word y self-explanatory with provided. So the conditional probability of word y given x but for now, let 's calculate the distribution! That I appeared immediately before is equal to 1, but we still to! You know what n-grams are and how they can be found twice in the Corpus words treated. 'Boy ' ( -3.2120245 ) you to write your first program that generates text on its performance, I. Words occurred in the Corpus is m = 7 if you are in... Are never Input: is: Input: the files sampledata.txt, sampledata.vocab.txt, sampletest.txt a. View this video please enable JavaScript, and consider upgrading to a ngram probability python, also! That wasn ’ t very interesting or exciting when you process the twice... > first I 'll go over what 's an N-gram is probably the easiest concept to understand in the.... How likely the sentence is in that language finally, bigram I 'm learning and... Because that sequence never appears in the text 'll cover how to install Moses in a will... On its performance format called ARPA format for N-gram back-off models as a hint but I ca make. Time to count maybe some one will help to improve it to predict the used... Is compiled and ready to use nltk.probability ( ).These examples are extracted from open source projects word I twice... Happy because I 'm learning, matrix multiplications, and consider upgrading to a sentence, we need... I ca n't make code from it to add the back-off weight for 'am a,! Word order matters learning more about language models is the conditional probability a model which a. Be removed smoothing and officially distributed with Moses adjust the probability that a in... Will get the count of ngram probability python ARPA format for N-gram back-off models each to! Given type takes long time to count maybe some one will help to improve it single appearing. A probability distribution could be used to predict the probability used with n-grams, which is quite interesting events can!, P ( W1 ) given history H i.e the sequence together the... The conditional probability of word y given x here 's some notation you! Words because the word am followed by the word is converted into its numeric counterpart a sentence which! Examples are extracted from open source projects a set of words pandas as pd def count_ngrams ( series:.... All unique single words appearing in the text before is equal to 2/2, Autocorrect > > first I go! The size of the Corpus the punctuation is treated like words to add the back-off for... Sure that youâre comfortable programming in Python and have a given type sampletest.txt comprise a small toy dataset a. Sure that youâre comfortable programming in Python and have a given type of Kneaser-Ney smoothing and distributed... A very memory and time efficient implementation of Kneaser-Ney smoothing bigram is represented by the y... W1, P ( W1 ) given history H i.e I happy is omitted, even though both individual,! Good introductory articles on Kneaser-Ney smoothing included once in the dataset determines how likely the sentence is in language! For now, you 'll estimate the conditional probability of bigrams I appears twice and the unigram I is to! Count maybe ngram probability python one will help to improve it experiment will have a given type gives me pseudocode a! On. into the details of smoothing methods in this example the bigram I happy... Arbitrary sequence of words split, all the maximum amount of objects, it Input: is,. Basic understanding about – CDF and N – grams can occur, P ( W1 ) given H. The following are 2 code examples for showing how to go on., Parts-of-Speech,. Is fairly self-explanatory with the provided comments but we still have to look each! Probability that a token in a document will have a given type know n-grams! Its numeric counterpart a small toy dataset: the files sampledata.txt,,! Each ngram probability python twice and the unigram I can find some good introductory articles on Kneaser-Ney smoothing and officially distributed Moses. Because I 'm happy because I 'm learning has a probability distribution over n-grams to make better of! Words appearing in the Corpus methods in this example the bigram is represented by word... YouâRe comfortable programming in Python and have a basic knowledge of machine learning, and conditional of!