string_manipulation.jl

s1 = "The quick brown fox jumps over the lazy dog α,β,γ"

# [search](https://docs.julialang.org/en/v1/base/strings/#Base.findfirst-Tuple{AbstractString,AbstractString}) returns the first index of a char
i = findfirst(isequal('b'), s1)
println(i)
#> 11
# the second argument is equivalent to the second argument of split, see below

# or a range if called with another string
r = findfirst("brown", s1)
println(r)
#> 11:15


# string [replace](https://docs.julialang.org/en/v1/base/strings/#Base.replace-Tuple{AbstractString,Pair}) is done thus:
r = replace(s1, "brown" => "red")
show(r); println()
#> "The quick red fox jumps over the lazy dog α,β,γ"

# search and replace can also take a regular expressions by preceding the string with 'r'
r = findfirst(r"b[\w]*n", s1)
println(r)
#> 11:15

# again with a regular expression
r = replace(s1, r"b[\w]*n" => "red")
show(r); println()
#> "The quick red fox jumps over the lazy dog α,β,γ"

# there are also functions for regular expressions that return RegexMatch types
# [match](https://docs.julialang.org/en/v1/base/strings/#Base.match) scans left to right for the first match (specified starting index optional)
r = match(r"b[\w]*n", s1)
println(r)
#> RegexMatch("brown")

# RegexMatch types have a property match that holds the matched string
show(r.match); println()
#> "brown"

# [eachmatch](https://docs.julialang.org/en/v1/base/strings/#Base.eachmatch) returns an iterator over all the matches
r = eachmatch(r"[\w]{4,}", s1)
for i in r print("\"$(i.match)\" ") end
#> "quick" "brown" "jumps" "over" "lazy"
println()


r = collect(m.match for m = eachmatch(r"[\w]{4,}", s1))
println(r)
#> SubString{String}["quick", "brown", "jumps", "over", "lazy"]

# a string can be repeated using the [repeat](http://julia.readthedocs.org/en/latest/manual/strings/#common-operations) function, 
# or more succinctly with the [^ syntax](https://docs.julialang.org/en/v1/base/strings/#Base.:^-Tuple{AbstractString,Integer}):
r = "hello "^3
show(r); println() #> "hello hello hello "

# the [strip](https://docs.julialang.org/en/v1/base/strings/#Base.strip) function works the same as python:
# e.g., with one argument it strips the outer whitespace
r = strip("hello ")
show(r); println() #> "hello"
# or with a second argument of an array of chars it strips any of them;
r = strip("hello ", ['h', ' '])
show(r); println() #> "ello"
# (note the array is of chars and not strings)

# similarly [split](https://docs.julialang.org/en/v1/base/strings/#Base.split) works in basically the same way as python:
r = split("hello, there,bob", ',')
show(r); println() #> SubString{String}["hello", " there", "bob"]
r = split("hello, there,bob", ", ")
show(r); println() #> SubString{String}["hello", "there,bob"]
r = split("hello, there,bob", [',', ' '], limit=0, keepempty=false)
show(r); println() #> SubString{String}["hello", "there", "bob"]
# (the last two arguements are limit and include_empty, see docs)

# the opposite of split: [join](https://docs.julialang.org/en/v1/base/strings/#Base.join) is simply
r = join(collect(1:10), ", ")
println(r) #> 1, 2, 3, 4, 5, 6, 7, 8, 9, 10