Pyspark Concat Array

Preamble: Twos-Complement Numbers. Here in this example, we shall take two arrays one will hold even values and another will hold odd values and we shall concate to. In PySpark, however, there is no way to infer the size of the dataframe partitions. Scala String Concatenation, Scala String Functions, Scala String format, Scala String length, Scala String substring, printf, split, trim example code. There is no concept of input and output features in time series. we can using CONCAT_WS in Apache Spark Dataframe and Spark SQL APIs. (Although I've written "array", the same technique also works. Already have an account? Sign in. This can be done quite. Assumption is that during mapping, pyspark will be able to translate array to array>. If it doesn't work, check whether the particular class you are looking for is present in the jar file or not. get_value(ds, i)) end end sas. Spark RDD flatMap() In this Spark Tutorial, we shall learn to flatMap one RDD to another. GROUP_CONCAT([ALL | DISTINCT] expression [, separator]) Usage notes: concat() and concat_ws() are appropriate for concatenating the values of multiple columns within the same row, while group_concat() joins together values from different rows. Weka, Solidity, Org. Pyspark add column from another dataframe. 摘要:在Spark开发中,由于需要用Python实现,发现API与Scala的略有不同,而Python API的中文资料相对很少。每次去查英文版API的说明相对比较慢,还是中文版比较容易get到所需,所以利用闲暇之余将官方文档翻译为中文版,并亲测Demo的代码。. date or datetime. In a way, this is like a Python list , but we specify a type at the time of creation. First, let us create a dataFrame and see how we can use CONCAT function work. I cobbled up an example to focus on my problem with changing the. asfarray Convert input to a floating point ndarray. They are extracted from open source Python projects. concat() methods help in joining, merging and concating different dataframe. Pyspark add column from another dataframe. Here is one way to do it, in case it is still useful: I ran this in pyspark shell, Python version 2. melt (frame, id_vars=None, value_vars=None, var_name=None, value_name='value', col_level=None) [source] ¶ Unpivot a DataFrame from wide format to long format, optionally leaving identifier variables set. transpose (self, *args, **kwargs) [source] ¶ Transpose index and columns. DataFrame, obtained from randomSplit as (td1, td2, td3,. Internally, date_format creates a Column with DateFormatClass binary expression. get_value(ds, i)) end end sas. i am using pyspark 1. ArrayType(). DataFrame的单元格可以存放数值、字符串等,这和excel表很像。同时DataFrame可以设置列名columns与行名index,可以通过像matlab一样通过位置获取数据也可以通过列名和行名定位,比较像matlab里面的table格式。. You can vote up the examples you like or vote down the ones you don't like. Transact-SQL Syntax Conventions. If you could change the schema design so that the data keys become the values, it would go a long way in making it easier for you to do some aggregation operations on the data. In C++, there are two types of comments, line comments, and block comments. You can vote up the examples you like or vote down the ones you don't like. data one (drop = i); array a x1 x2 x3 x4 x5; do i = 1 to 5; do over a; a = ranuni(i); end; output; end; run; proc lua; submit; local ds = sas. How can i modify it so that it can cater the case of y=0 too. They can be constructed from a wide array of sources such as an existing RDD in our case. Assumption is that during mapping, pyspark will be able to translate array to array>. Arrays and lists are both used in Python to store data, but they don't serve exactly the same purposes. For these reasons, we are excited to offer higher order functions in SQL in the Databricks Runtime 3. A SparkSession can be used create DataFrame, register DataFrame as tables, execute SQL over tables, cache tables, and read parquet files. tolist ¶ Return the array as an a. Python is a high level open source scripting language. In fact the dates are treated as strings in Hive. pyspark官方文档中的pyspark. i am using pyspark 1. Return a copy of the array data as a (nested) Python list. For NULL or a JSON null input, returns NULL. Word2Vec is an Estimator which takes sequences of words representing documents and trains a Word2VecModel. There are different ways to do that, and we will discuss the most common methods. I also changed the semantics of concat w. I have a pyspark dataframe consisting of one column, called json, where each row is a unicode string of json. In this case we're not interested in changing existing array elements. Getting started with PySpark - Part 2 In Part 1 we looked at installing the data processing engine Apache Spark and started to explore some features of its Python API, PySpark. pyspark中操作spark sql问题 [问题点数:40分,无满意结帖,结帖人kyo1979]. The old way would be to do this using a couple of loops one inside the other. Data items are converted to the nearest compatible Python type. In this release, there are some new major features added to Spark SQL and Structured…. utils import np_utils import numpy as np import matplotlib. I am trying to run a simple command that guesses gender by name using multiprocessing. For example, the above demo needs org. So basically I get the known data into the form Array(ID, Seq[(wavelength, intensity)]) after using sequence of map and groupByKey actions. The generated ID is guaranteed to be monotonically increasing and unique, but not consecutive. Concatenation. encoding: {None, str}, optional. It is an improvement over more the traditional bag-of-word model encoding schemes where large sparse vectors were used to represent each word or to score each word within a vector to represent an entire vocabulary. The reduce function is a little less obvious in its intent. Python Installation; 3. concat(item. The Microsoft Access database engine selects all of the records that meet the conditions in the SQL statement. write the rules to extract the data and let Scrapy do the rest. By voting up you can indicate which examples are most useful and appropriate. transpose¶ DataFrame. This is a guest community post from Li Jin, a software engineer at Two Sigma Investments, LP in New York. feature函数中文简介 04-28 阅读数 2300 可以看成对pyspark. com | Latest informal quiz & solutions at. close(ds) for i, item in pairs(tbl) do print(i, table. When percentage is an array, each value of the percentage array must be between 0. These are not necessarily sparse in the typical "mostly 0". Since Index is immutable, the underlying data can be safely shared and a copy is not needed. The new text will appear in the box at the bottom of the page. First, let us create a dataFrame and see how we can use CONCAT function work. If you do not want complete data set and just wish to fetch few records which satisfy some condition then you can use FILTER function. Now there are various ways in Python, through which we can perform the Intersection of the lists. Each topic. Because of this sometimes there is a need to dynamically create a SQL statement on the fly and then run that command. close(ds) for i, item in pairs(tbl) do print(i, table. Must fulfill input requirements of last step of pipeline’s inverse_transform method. In this article, we are going to build an end-to-end machine learning model using MLlib in pySpark. The date functions are listed below. In Python, you can also achieve the same results by doing a simple addition. Rather, you can view these objects as being "compressed" where any data matching a specific value (NaN / missing value, though any value can be chosen, including 0) is omitted. Using the static String. Definition and Usage. Concatenation of Series and DataFrame objects is very similar to concatenation of Numpy arrays, which can be done via the np. Can one of you tell me if there's a better way of doing this? Here's what I'm trying to do: I want a generic. View Preeyank Pable’s profile on LinkedIn, the world's largest professional community. 6 and later. In some applications, having hard coded SQL statements is not appealing because of the dynamic nature of the queries being issued against the database server. Ask Question Is there any way to transform the WrappedArrays into concatenated arrays? Or can I do it differently?. Tech Share is Alibaba Cloud’s incentive program to encourage the sharing of technical knowledge and best practices within the cloud community. There is no concept of input and output features in time series. x git excel windows xcode multithreading pandas database reactjs bash scala algorithm eclipse. This helps store many values in a single database field. In my experience, as long as the partitions are not 10KB or 10GB but are in the order of MBs, then the partition size shouldn't be too much of a problem. In this chapter, we will discuss Scala String in Detail. join or concatenate string in pandas python - Join() function is used to join or concatenate two or more strings in pandas python with the specified separator. fromfunction Construct an array by executing a function on grid. One way uses the string. Learn the four main approaches to string formatting in Python, as well as their strengths and weaknesses. In case of substring startIndex is inclusive and endIndex is exclusive. All of these operators share something in common -- they are "bitwise" operators. For example, the above demo needs org. Also create a user interface to do a search using that inverted index which returns a list of files that contain the query term / terms. melt¶ pandas. Copy with detailed index positions to copy the two. APPLIES TO: SQL Server Azure SQL Database Azure SQL Data Warehouse Parallel Data Warehouse. You can vote up the examples you like or vote down the exmaples you don't like. These functions let us easily modify and manipulate strings. In this case, numpy has some built-in functions: Concatenate. 摘要:在Spark开发中,由于需要用Python实现,发现API与Scala的略有不同,而Python API的中文资料相对很少。每次去查英文版API的说明相对比较慢,还是中文版比较容易get到所需,所以利用闲暇之余将官方文档翻译为中文版,并亲测Demo的代码。. Python Pandas Concatenation is a process of joining of the object along an axis. hive splict, explode, lateral view, concat_ws. Driver and you need to download it and put it in jars folder of your spark installation path. concat(*cols): 把多个输入类型为字符串的列合并成为一列。 concat_ws(sep, *cols): Concatenates multiple input string columns together into a single string column, using the given separator. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type. All of these operators share something in common -- they are "bitwise" operators. DataFrame groupBy and concat non-empty strings Question by jestin ma Jul 13, 2016 at 04:57 AM spark-sql Falcon dataframe concatenate I want to concatenate non-empty values in a column after grouping by some key. But when I try to use any Spark actions on Seq[(wavelength, intensity)] with the observed data (which is a Spark. Because if one of the columns is null, the result will be null even if one of the other columns do have information. 1 installed and available in the cluster or an `ImportError` will be raised to indicate an upgrade is needed. In general, this means minimizing the amount of data transfer across nodes, since this is usually the bottleneck for big data analysis problems. The join() method is a string method and returns a string in which the elements of sequence have been joined by str separator. [SPARK-8241][SQL] string function: concat_ws. Matrix which is not a type defined in pyspark. tolist¶ ndarray. Reading from the bottom to the top, this graph shows exactly what will happen with our computation: first the array x is ingested by dd. xgboost 预测的例子 优化前 每条数据都转化为 pd,增加了额外开销。. In this tutorial, we shall learn the usage of RDD. Toggle navigation Close Menu. They preserve time of day data (if that is at all important to you). Read a directory of binary files from HDFS, a local file system (available on all nodes), or any Hadoop-supported file system URI as a byte array. Version 2 May 2015 - [Draft – Mark Graph – mark dot the dot graph at gmail dot com – @Mark_Graph on twitter] 3 Working with Columns A DataFrame column is a pandas Series object. Pyspark recipes manipulate datasets using the PySpark / SparkSQL "DataFrame" API. This extension contains many useful methods for aggregating numeric values. If the encoding is something other than 'bytes' or 'latin1' you will not be able to load the file in NumPy versions < 1. , an offset of 2 returns the expr value with an interval of 2 rows. NOAA's operational definitions of El Niño and La Niña conditions are based upon the Oceanic Niño Index [ONI]. Note that because the function takes list, you can. They are extracted from open source Python projects. Here is the cheat sheet I used for myself when writing those codes. withColumn cannot be used here since the matrix needs to be of the type pyspark. Each topic. These are not necessarily sparse in the typical "mostly 0". They are essentially look-at-only. 摘要:在Spark开发中,由于需要用Python实现,发现API与Scala的略有不同,而Python API的中文资料相对很少。每次去查英文版API的说明相对比较慢,还是中文版比较容易get到所需,所以利用闲暇之余将官方文档翻译为中文版,并亲测Demo的代码。. Merge with outer join "Full outer join produces the set of all records in Table A and Table B, with matching records from both sides where available. The loop way. At the same time Array differs by lists as they are of some specific size, while lists size can be changed and controlled at runtime. Operations in PySpark DataFrame are lazy in nature but, in case of pandas we get the result as soon as we apply any operation. It takes comma separated values as the input parameter, iterates through it as long as it finds a comma in the value, takes each value before the comma, inserts into a table. The sample column contains 2 arrays, which they are correlated to each other 1 to 1. the objective of this competition was to identify if loan applicants are capable of repaying their loans based on the data that was collected from each. For a simple problem like this, you could also use the explode function. The few differences between Pandas and PySpark DataFrame are: Operation on Pyspark DataFrame run parallel on different nodes in cluster but, in case of pandas it is not possible. The dtype will be a lower-common-denominator dtype (implicit upcasting); that is to say if the dtypes (even of numeric types) are mixed, the one that accommodates all will be chosen. windows上搭建pyspark环境,并使用pyspark连接hive由于最近有使用python连接hive,编写spark程序的需求,所以开始搭建pyspark的windows开发环境开发环境:p 博文 来自: weixin_43942345的博客. Arguments¶ expr. First, let us create a dataFrame and see how we can use CONCAT function work. def monotonically_increasing_id (): """A column that generates monotonically increasing 64-bit integers. then use the position in the array to order the elements of the array. scale_ scale_: ndarray, shape (n_features,) Per feature relative scaling of the data. Starting from numpy 1. pySpark | pySpark. MyRegExLoader , for custom record delimiter converted newlines to null using PIG and used newline as record delimiter. Viewed 33k times 12. 2 Manual! MongoDB is a document database designed for ease of development and scaling. In my experience, as long as the partitions are not 10KB or 10GB but are in the order of MBs, then the partition size shouldn't be too much of a problem. For a complete list of methods available, please check official documentation of Scala. We get the latter by exploiting the functionality of pyspark. Date data types do not exist in Hive. Pandas is built on top of Numpy and designed for practical data analysis in Python. String Array Declaration with Specific Size. Time Series data must be re-framed as a supervised learning dataset before we can start using machine learning algorithms. 3, “Date and Time Types” , for a description of the range of values each date and time type has and the valid formats in which values may be specified. I am looking to return a list of users from a database. fromfunction Construct an array by executing a function on grid. Pandas is an open-source, BSD-licensed Python library providing high-performance, easy-to-use data structures and data analysis tools for the Python programming language. 背景 pandas dataFrame 无法支持大量数据的计算,可以尝试 spark df 来解决这个问题。 一. Data Engineers Will Hate You - One Weird Trick to Fix Your Pyspark Schemas May 22 nd , 2016 9:39 pm I will share with you a snippet that took out a lot of misery from my dealing with pyspark dataframes. pySpark | pySpark. How to combine multiple columns into one in Apache Spark Dataframes? Using CONCAT function in Apache Spark Dataframe and SQL API, we can concatenate multiple columns in a dataframe into a single column. frame objects, statistical functions, and much more - pandas-dev/pandas. Concatenates array elements using supplied delimiter and optional null string and returns the resulting string. mul Multiply DataFrames. If you do not have PySpark on Jupyter Notebook, I found this tutorial useful:. portrait分割数据增强,需要对image和mask同步处理: featurewise结果: from keras. open("one") local tbl = {} for var in sas. Since Index is immutable, the underlying data can be safely shared and a copy is not needed. StreamingContext. If the encoding is something other than ‘bytes’ or ‘latin1’ you will not be able to load the file in NumPy versions < 1. pdf - scribd. com/public/yb4y/uta. If you do not want complete data set and just wish to fetch few records which satisfy some condition then you can use FILTER function. xgboost 预测的例子 优化前 每条数据都转化为 pd,增加了额外开销。. Scala Array Methods. def monotonicallyIncreasingId (): """A column that generates monotonically increasing 64-bit integers. We shall take two arrays and then based on some constraint, will copy their content into one single array. View All Categories. Combinations are emitted in lexicographic sort order. In this tutorial, we learn to get unique elements of an RDD using RDD. php(143) : runtime-created function(1) : eval()'d code(156) : runtime-created. 7 Date and Time Functions This section describes the functions that can be used to manipulate temporal values. data one (drop = i); array a x1 x2 x3 x4 x5; do i = 1 to 5; do over a; a = ranuni(i); end; output; end; run; proc lua; submit; local ds = sas. Apache Spark. First, let us create a dataFrame and see how we can use CONCAT function work. Learning Objectives. They are extracted from open source Python projects. By voting up you can indicate which examples are most useful and appropriate. Tech Share is Alibaba Cloud’s incentive program to encourage the sharing of technical knowledge and best practices within the cloud community. You can vote up the examples you like or vote down the ones you don't like. The flatMap() method first maps each element using a mapping function, then flattens the result into a new array. In this post, I am sharing a script to perform concatenation of strings by applying GROUP BY in SQL Server. mysql - CONCAT多个字段到单个字段,单个间隔 ; 5. The concat_ws and split Spark SQL functions can be used to add ArrayType columns to DataFrames. Note: Index starts from 0. For NULL or a JSON null input, returns NULL. Matrix which is not a type defined in pyspark. This walkthrough uses HDInsight Spark to do data exploration and binary classification and regression modeling tasks on a sample of the NYC taxi trip and fare 2013 dataset. The SPLIT function splits the string around the pattern pat and returns an array of strings. In many "real world" situations, the data that we want to use come in multiple files. In this case, returns the approximate percentile array of column col at the given percentage array. extensible by design, plug new functionality easily without having to touch the core. add Add DataFrames. In Python, there are a few ways to concatenate - or combine - strings. You can create a new array with the size of the total of the two arrays. A SparkSession can be used create DataFrame, register DataFrame as tables, execute SQL over tables, cache tables, and read parquet files. Confidential Information. You can vote up the examples you like or vote down the ones you don't like. The loop way. Subscribe to our Newsletter, and get personalized recommendations. But when I try to use any Spark actions on Seq[(wavelength, intensity)] with the observed data (which is a Spark. name] = {} end while sas. Example - Concatenate two Datasets In the following example, we have two Datasets with employee information read from different data files. [SPARK-8241][SQL] string function: concat_ws. join(), and df. How can i modify it so that it can cater the case of y=0 too. This means that users will need to have at least pyarrow 0. 但这些都没有帮助我解决为什么这不起作用。我正在使用pyspark 1. This is a collection of a type of values. The variety and quantity of data that is available today through the internet is like a treasure trove of secrets and mysteries waiting to be solved. This website uses cookies for analytics, personalisation and advertising. In order to concat dataframe, we use concat() function which helps in concatenating a dataframe. Depending on the configuration, the files may be saved locally, through a Hive metasore, or to a Hadoop file system (HDFS). combinations_with_replacement (iterable, r) ¶ Return r length subsequences of elements from the input iterable allowing individual elements to be repeated more than once. Each file is read as a single record and returned in a key-value pair, where the key is the path of each file, the value is the content of each file. They are extracted from open source Python projects. Along with that, it provides a gamut of high-level functions to perform mathematical operations on these structures. next(ds) do for i, v in pairs(tbl) do table. First, let us create a dataFrame and see how we can use CONCAT function work. In this chapter, we will discuss Scala String in Detail. What changes were proposed in this pull request? The PR adds a logic for easy concatenation of multiple array columns and covers: Concat expression has been extended to support ar. Scikit-Learn comes with many machine learning models that you can use out of the box. TO_ARRAY¶ Converts the input expression into an array: If the input is an ARRAY, or VARIANT containing an array value, the result is unchanged. Rather, you can view these objects as being "compressed" where any data matching a specific value (NaN / missing value, though any value can be chosen, including 0) is omitted. ravel Return a flattened array. Internally, Java creates a new character array with combined length of string object and argument string, and copies all content from both strings into this new array. foldLeft can be used to eliminate all whitespace in multiple columns or…. Ask Question Asked 1 year, 6 months ago. The variety and quantity of data that is available today through the internet is like a treasure trove of secrets and mysteries waiting to be solved. Examples >>>. Q&A for Work. Along with that, it provides a gamut of high-level functions to perform mathematical operations on these structures. Apache Spark flatMap Example As you can see in above image RDD X is the source RDD and RDD Y is a resulting RDD. Introduction¶. The Powerful Python page contains links to more articles as well as a list of future articles. The Manual introduces key concepts in MongoDB, presents the query language, and provides operational and administrative considerations and procedures as well as a comprehensive reference section. How to select particular column in Spark(pyspark)? Is there any way to read Xlsx file in pyspark?Also want to read strings of column from each columnName. net-mvc xml wpf angular spring string ajax python-3. Merging multiple data frames row-wise in PySpark. First, let us create a dataFrame and see how we can use CONCAT function work. In this article, we are going to build an end-to-end machine learning model using MLlib in pySpark. The following are code examples for showing how to use pyspark. You'll also get a simple rule of thumb for how to pick the best general purpose string formatting approach in your own programs. In general, this means minimizing the amount of data transfer across nodes, since this is usually the bottleneck for big data analysis problems. StreamingContext. Q&A for Work. Many people confuse it with BLANK or empty string however there is a difference. Once you have written or read all of the desired data for a file object you need to close the file so that resources can be reallocated on the operating system that the code is running on. My research interests lie at the intersection of computer vision and multimedia. simpleString, except that top level struct type can omit the struct<> and atomic types use typeName() as their format, e. There is no concept of input and output features in time series. concat method is static and count, sorted and distinct methods are called on stream object created by stream() method calling on collection. data one (drop = i); array a x1 x2 x3 x4 x5; do i = 1 to 5; do over a; a = ranuni(i); end; output; end; run; proc lua; submit; local ds = sas. In a way, this is like a Python list , but we specify a type at the time of creation. 行列之间的互相转换是ETL中的常见需求,在Spark SQL中,行转列有内建的PIVOT函数可用,没什么特别之处。而列转行要稍微麻烦点。. xgboost 预测的例子 优化前 每条数据都转化为 pd,增加了额外开销。. You can vote up the examples you like or vote down the ones you don't like. Otherwise, it returns as string. ascending – Optional Boolean array to denote sorting direction for each sorting column. Methods like reduceByKey() by default use their own combiner to combine the data locally in each Partition, for a given key. This method performs an ordinal (case-sensitive and culture-insensitive) search to find oldValue. In Dataframe df. There are two classes pyspark. concat([df1, df2]), you can simply call df1. python实现数据库中两行相减并依次更新(类似于加速度计算) #数据库中的数据为轨迹数据,包括多辆出租车的多时段定位。 因此首先根据出租车编号,定位时间排序,这样可以做到依. Inner query is used to get the array of split values and the outer query is used to assign each value to a separate column. Word Embedding. Is there any function in Spark SQL or DataFrame API to concatenate multiple columns in a dataframe? Solution: Yes. js sql-server iphone regex ruby angularjs json swift django linux asp. Given a set of text files, implement a program to create an inverted index. To learn more or change your cookie settings, please read our Cookie Policy. If input x is an array, then this is an array of length nbins. Methods like reduceByKey() by default use their own combiner to combine the data locally in each Partition, for a given key. groupby('country'). Join method is a quick way to get a comma-delimited string. Working in Pyspark: Basics of Working with Data and RDDs This entry was posted in Python Spark on April 23, 2016 by Will Summary : Spark (and Pyspark) use map, mapValues, reduce, reduceByKey, aggregateByKey, and join to transform, aggregate, and connect datasets. This walkthrough uses HDInsight Spark to do data exploration and train binary classification and regression models using cross-validation and hyperparameter optimization on a sample of the NYC taxi trip and fare 2013 dataset. As shown above, you would have to import Array. class pyspark. The new string that is created is referred to as a string object. 行列之间的互相转换是ETL中的常见需求,在Spark SQL中,行转列有内建的PIVOT函数可用,没什么特别之处。而列转行要稍微麻烦点。. Happy Coding! Morten Wennevik [C# MVP]. simpleString, except that top level struct type can omit the struct. This code shows you how to take an array and convert it into a string delimited by commas in one nline. java,json,eclipse,jar,import. At the same time Array differs by lists as they are of some specific size, while lists size can be changed and controlled at runtime. If input x is an array, then this is an array of length nbins. For NULL or a JSON null input, returns NULL. def column_concat(a,b): return concat(a,b) searches_df = searches_df. tolist¶ method. new_col_name – Optional String to denote the new column names. A Resilient Distributed Dataset (RDD), the basic abstraction in Spark. Machine learning to predict San Francisco crime July 20, 2015 July 20, 2015 Damien RJ Case studies In today’s post, we document our submission to the recent Kaggle competition aimed at predicting the category of San Francisco crimes, given only their time and location of occurrence. For example, rather than calling pd. Explode a column with a List of Jsons with Pyspark. The sample column contains 2 arrays, which they are correlated to each other 1 to 1. The pandas package provides various methods for combining DataFrames including merge and concat. bucketing=true;) every time before we write data to the bucketed table. True for ascending, False for descending. Each file is read as a single record and returned in a key-value pair, where the key is the path of each file, the value is the content of each file. tolist()¶ Return the array as a (possibly nested) list. To create a basic instance, all we need is a SparkContext reference. The CONCAT_WS function is similar to the CONCAT function. but think I can figure it out based on how it's done in pyspark. distinct() method with the help of Java, Scala and Python examples. PySpark recipes¶ DSS lets you write recipes using Spark in Python, using the PySpark API. Conversion between byte array and string may be used in many cases including IO operations, generate secure hashes etc. NOAA's operational definitions of El Niño and La Niña conditions are based upon the Oceanic Niño Index [ONI]. If it doesn't work, check whether the particular class you are looking for is present in the jar file or not. net-mvc xml wpf angular spring string ajax python-3. What is important to remember is that the character that joins the elements is the one upon which the function is called.