Split a string every 5 characters

Question

Suppose I have a long string:

"XOVEWVJIEWNIGOIWENVOIWEWVWEW"

How do I split this to get every 5 characters followed by a space?

"XOVEW VJIEW NIGOI WENVO IWEWV WEW"

Note that the last one is shorter.

I can do a loop where I constantly count and build a new string character by character but surely there must be something better no?

Solution 1

Using regular expressions:

gsub("(.{5})", "\\1 ", "XOVEWVJIEWNIGOIWENVOIWEWVWEW")
# [1] "XOVEW VJIEW NIGOI WENVO IWEWV WEW"

Solution 2

Using sapply

> string <- "XOVEWVJIEWNIGOIWENVOIWEWVWEW"
> sapply(seq(from=1, to=nchar(string), by=5), function(i) substr(string, i, i+4))
[1] "XOVEW" "VJIEW" "NIGOI" "WENVO" "IWEWV" "WEW"  

Solution 3

You can try something like the following:

s <- "XOVEWVJIEWNIGOIWENVOIWEWVWEW" # Original string
l <- seq(from=5, to=nchar(s), by=5) # Calculate the location where to chop

# Add sentinels 0 (beginning of string) and nchar(s) (end of string)
# and take substrings. (Thanks to @flodel for the condense expression)
mapply(substr, list(s), c(0, l) + 1, c(l, nchar(s))) 

Output:

[1] "XOVEW" "VJIEW" "NIGOI" "WENVO" "IWEWV" "WEW"

Now you can paste the resulting vector (with collapse=' ') to obtain a single string with spaces.

Solution 4

No *apply stringi solution:

x <- "XOVEWVJIEWNIGOIWENVOIWEWVWEW"
stri_sub(x, seq(1, stri_length(x),by=5), length=5)
[1] "XOVEW" "VJIEW" "NIGOI" "WENVO" "IWEWV" "WEW" 

This extracts substrings just like in @Jilber answer, but stri_sub function is vectorized se we don't need to use *apply here.

Solution 5

You can also use a sub-string without a loop. substring is the vectorized substr

x <- "XOVEWVJIEWNIGOIWENVOIWEWVWEW"
n <- seq(1, nc <- nchar(x), by = 5) 
paste(substring(x, n, c(n[-1]-1, nc)), collapse = " ")
# [1] "XOVEW VJIEW NIGOI WENVO IWEWV WEW"

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Comments

[rawr]

should be pasted and collapsed methinks

[user1357015]

This looks great, I can paste and collapse from here. But would you mind giving some insight onto how that mapply works? Thanks!

[musically_ut]

@user1357015 Added some comments.

[user1357015]

@flodel, can you help explain "\\1 "? I've figured everything else out but that stumbles me

[Tyler Rinker]

@user1357015 I think hwnd does a nice job explaining this idea here: stackoverflow.com/a/26495062/1000343

[Brian D]

this is awesome, and super fast :)

[Lasarus9]

What would be the way to reverse this? For example, how would you do this starting from the right, and going to left? Also, instead of splitting by 5, lets say i want the first 8 characters and the last 6 characters separated, so it would look like: ` "XOVEWVJI EWNIGOIWENVOIW EWVWEW" `