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r_workshop5 [2018/11/14 16:28] katherinehebert [for loop] |
r_workshop5 [2018/11/14 16:37] katherinehebert [Pay attention to the next tips!] |
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| </code> | </code> | ||
| - | Tip1. To loop over the number of rows of a data frame, we can use the function ''nrow()'' | + | **Tip 1.** To loop over the number of rows of a data frame, we can use the function ''nrow()'' |
| <code rsplus> | <code rsplus> | ||
| Line 297: | Line 297: | ||
| </code> | </code> | ||
| - | Tip2. If we want to perform operations on the elements of one column, we can directly iterate over it | + | **Tip 2.** If we want to perform operations on the elements of one column, we can directly iterate over it |
| <code rsplus> | <code rsplus> | ||
| Line 305: | Line 305: | ||
| </code> | </code> | ||
| - | The expression within the loop can be almost anything and is usually a compound statement containing many commands. | + | **Tip 3.** The expression within the loop can be almost anything and is usually a compound statement containing many commands. |
| <code rsplus> | <code rsplus> | ||
| Line 917: | Line 917: | ||
| Proper indentation and spacing is the first step to get an easy to read code: | Proper indentation and spacing is the first step to get an easy to read code: | ||
| - | Use spaces between and after you operators; | + | * Use spaces between and after you operators |
| - | Use consistentely the same assignation operator. <- is often preferred. = is OK, but do not switch all the time between the two; | + | * Use consistently the same assignation operator. <- is often preferred. = is OK, but do not switch all the time between the two |
| - | Use brackets when using flow control statements: | + | * Use brackets when using flow control statements: |
| + | * Inside brackets, indent by *at least* two spaces; | ||
| + | * Put closing brackets on a separate line, except when preceding an `else` statement. | ||
| + | * Define each variable on its own line. | ||
| - | - Inside brackets, indent by *at least* two spaces; - Put closing brackets on a separate line, except when preceding an `else` statement. | + | This code is not spaced, and therefore hard to read. All brackets are badly aligned, and it looks "messy". |
| - | - Define each variable on its own line. | + | |
| - | + | ||
| - | code is not spaced. All brackets are in the same line, and it looks "messy". | + | |
| <code rsplus> | <code rsplus> | ||
| a<-4;b=3 | a<-4;b=3 | ||
| Line 932: | Line 932: | ||
| </code> | </code> | ||
| - | it looks more organized, no? | + | This looks more organized, no? |
| <code rsplus> | <code rsplus> | ||
