@@ -144,6 +144,27 @@ In the 'Environment' window you will also get a table:
144144The 'Environment' window allows you to keep track of the objects you have
145145created in R.
146146
147+
148+ ::::::::::::::::::::::::::::::::::::::::: callout
149+
150+ ## Tip: Use of white space for readability
151+
152+ The white spaces surrounding the assignment operator ` <- ` in the example
153+ above (` first_value <- 1 ` ) are unnecessary. However, including them does make your code
154+ easier to read. There are several style guides you can follow, and choosing
155+ one is up to you, but consistency is key!
156+
157+ A style guide we recommend is the Tidyverse [ style guide] ( https://style.tidyverse.org/ ) .
158+
159+ As they say:
160+
161+ "Good coding style is like correct punctuation: you can manage without it, butitsuremakesthingseasiertoread."
162+
163+ ::::::::::::::::::::::::::::::::::::::::::::::::::
164+
165+
166+
167+
147168::::::::::::::::::::::::::::::::::::::: challenge
148169
149170## Exercise: Create some objects in R
@@ -193,8 +214,9 @@ Here are some important details about naming objects in R.
193214 a colored highlight or RStudio gives you a suggested autocompletion you have
194215 chosen a name that has a reserved meaning.
195216- ** Use the recommended assignment operator** : In R, we use '\< - ' as the
196- preferred assignment operator. '=' works too, but is most commonly used in
197- passing arguments to functions (more on functions later). There is a shortcut
217+ preferred assignment operator, which is recommended by the Tidyverse
218+ [ style guide] ( https://style.tidyverse.org/ ) discussed above. '=' works too, but is most
219+ commonly used in passing arguments to functions (more on functions later). There is a shortcut
198220 for the R assignment operator:
199221 - Windows execution shortcut: <KBD >Alt</KBD >\+ <KBD >\- </KBD >
200222 - Mac execution shortcut: <KBD >Option</KBD >\+ <KBD >\- </KBD >
@@ -900,16 +922,19 @@ the vector you are searching:
900922# current value of 'snp_genes':
901923# chr [1:7] "OXTR" "ACTN3" "AR" "OPRM1" "CYP1A1" NA "APOA5"
902924
903- # test to see if "ACTN3" or "APO5A " is in the snp_genes vector
925+ # test to see if "ACTN3", "APO5A", or "actn3 " is in the snp_genes vector
904926# if you are looking for more than one value, you must pass this as a vector
905927
906- c(" ACTN3" ," APOA5" ) %in% snp_genes
928+ c(" ACTN3" ," APOA5" , " actn3 " ) %in% snp_genes
907929```
908930
909931``` output
910- [1] TRUE TRUE
932+ [1] TRUE TRUE FALSE
911933```
912934
935+ Notice that the gene "actn3" is FALSE? This is because character vectors are case sensitive, so
936+ keep this in mind when subsetting and selecting values from a character vector.
937+
913938::::::::::::::::::::::::::::::::::::::::: callout
914939
915940## Tip: What's the difference between the ` %in% and the ` ==` operators?
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