Wolfram Function Repository

Instant-use add-on functions for the Wolfram Language

Function Repository Resource:

 StringSplitBefore

Source Notebook

Split a string before each substring matching a string pattern

Contributed by: Ian Ford (Wolfram Research)

ResourceFunction["StringSplitBefore"]["string"]

splits "string" into a list of substrings before each whitespace.

ResourceFunction["StringSplitBefore"]["string",patt]

splits "string" into substrings before delimiters matching the string expression patt.

ResourceFunction["StringSplitBefore"]["string",{p1,p2,…}]

splits "string" before any of the pi.

ResourceFunction["StringSplitBefore"]["string",patt→val]

replaces each delimiter matching patt with val.

ResourceFunction["StringSplitBefore"]["string",{p1→v1,…}]

replaces each delimiter matching pi with vi.

ResourceFunction["StringSplitBefore"][{s1,s2,…},p]

gives the list of results for each of the si.

Details and Options

Unlike StringSplit, ResourceFunction["StringSplitBefore"] will not remove the delimiters—it will only split the string before each delimiter.
ResourceFunction["StringSplitBefore"][s,p] otherwise behaves like StringSplit[s,p,All].
ResourceFunction["StringSplitBefore"] takes the same options as StringSplit.

Examples

Basic Examples (2) 

Split a string before each whitespace (without removing the whitespace):

In[1]:=
ResourceFunction["StringSplitBefore"]["a bbb cccc aa d"]
Out[1]=

Split a string before every "--" (without removing the "--"):

In[2]:=
ResourceFunction["StringSplitBefore"]["a--bbb---ccc--dddd", "--"]
Out[2]=

Scope (7) 

Split before every run of spaces:

In[3]:=
ResourceFunction["StringSplitBefore"]["the cat in the hat"]
Out[3]=

Use string patterns:

In[4]:=
ResourceFunction["StringSplitBefore"]["192.168.0.1", "."]
Out[4]=
In[5]:=
ResourceFunction["StringSplitBefore"]["123 2.3 4 6", WhitespaceCharacter ..]
Out[5]=
In[6]:=
ResourceFunction["StringSplitBefore"]["11a22b3", _?LetterQ]
Out[6]=

Regular expressions:

In[7]:=
ResourceFunction[ "StringSplitBefore"]["A tree, an apple, four pears. And more: two sacks", RegularExpression["\\W+"]]
Out[7]=

Mix regular expressions and string patterns:

In[8]:=
ResourceFunction[ "StringSplitBefore"]["primes: 2 two 3 three 5 five ...", Whitespace ~~ RegularExpression["\\d"] ~~ Whitespace]
Out[8]=

Split into substrings before either delimiter:

In[9]:=
ResourceFunction["StringSplitBefore"]["a-b:c-d:e-f-g", {":", "-"}]
Out[9]=
In[10]:=
ResourceFunction["StringSplitBefore"]["a-b:c-d:e-f-g", ":" | "-"]
Out[10]=

Replace a delimiter:

In[11]:=
ResourceFunction["StringSplitBefore"]["a b::c d::e f g", "::" -> "--"]
Out[11]=

StringSplitBefore automatically threads over lists of strings:

In[12]:=
ResourceFunction[ "StringSplitBefore"][{"a:b:c:d", "listable:element"}, ":"]
Out[12]=

Options (1) 

Split a string before every "c", including uppercase letters:

In[13]:=
ResourceFunction["StringSplitBefore"]["cat Cat hat CAT", "c", IgnoreCase -> True]
Out[13]=

Version History

  • 1.0.0 – 25 September 2019

Related Resources

License Information