{"id":340,"date":"2013-09-30T19:14:16","date_gmt":"2013-09-30T19:14:16","guid":{"rendered":"http:\/\/www.pythonforspss.org\/?p=340"},"modified":"2015-01-27T07:54:17","modified_gmt":"2015-01-27T07:54:17","slug":"spss-index-function","status":"publish","type":"post","link":"https:\/\/www.spss-tutorials.com\/spss-index-function\/","title":{"rendered":"SPSS CHAR.INDEX Function – Find Characters in String"},"content":{"rendered":"\n\n

The SPSS CHAR.INDEX function returns the position of the first occurrence of a given expression within a string<\/a>. If the expression does not occur in the string, it returns a zero. Please note that string values are case sensitive.<\/p>\n\n\n\tSPSS Index FunctionSPSS Index Function Example<\/span>\n<\/span>\n\n\n

SPSS CHAR.INDEX Example<\/h2>\n\n

Say we have data holding some email addresses and we'd like to see which domains are used most. For each email address, the domain is everything after the @<\/code> sign. The syntax<\/a> below demonstrates how to do so. We'll first find the position of the first (and only)@<\/code> in step 2. Next, we'll substitute that into a SUBSTR<\/code> function in step 4.<\/p>\n\n\n

SPSS CHAR.INDEX Syntax Example I<\/h2>\n\n
*1. Create data.
<\/strong>
data list free\/email (a20).
begin data
stefan@hotmail.com anneke123@gmail.com ruben@yahoo.com erik1970@bkb.nl maarten1979bkb.nl
end data.

*2. Find position of first "@".
<\/strong>
compute first_a = char.index(email,'@').
exe.

*3. Declare new string variable for domain.
<\/strong>
string domain(a15).

*4. Extract domain from email address.
<\/strong>
compute domain = char.substr(email,char.index(email,'@') + 1).
exe.

*5. Correction for email without "@".
<\/strong>
if char.index(email,'@') = 0 domain = ''.
exe.<\/div>\n

Note that there's an error in the data since the last email address doesn't contain any @<\/code>. Therefore, first_@<\/code> is zero for this case. This makes step 4 come up with an incorrect domain<\/code>, hence the correction at the end.A better option here is to use a single IF<\/a> command that computes the domain only if @<\/code> is present in the email address.<\/span><\/p>\n\n\n

SPSS CHAR.INDEX - the Divisor<\/h2>\n\n

A little known feature of SPSS' CHAR.INDEX function is an optional third argument known as the divisor. The divisor divides the search expression into substrings of length n<\/em>. The position of the first occurrence of one of these substrings is returned. For example, in \nCHAR.INDEX(variable,'0123456789',1)<\/span> \nthe divisor is 1<\/code>. This breaks 0123456789<\/code> into substrings of length 1, rendering the digits 0<\/code> through 9<\/code>. The position of the first digit is now returned.<\/p>\n\n

The next syntax example extracts all digits from a string. It combines the use of the divisor with LOOP, SUBSTR<\/a> and CONCAT in order to do so. The last step uses ALTER TYPE<\/a> for converting it into a numeric variable<\/a>.<\/p>\n\n\n

SPSS CHAR.INDEX Syntax Example II<\/h2>\n\n
*1. Check whether any number is present in email.
<\/strong>
compute number_present = char.index(email,'0123456789',1) > 0.
exe.

*2. Declare new string.
<\/strong>
string numbers(a20).

*3. Loop through characters and pass each digit into string.
<\/strong>
loop #pos =1 to char.length(email).
if char.index(char.substr(email,#pos,1),'0123456789',1) > 0 numbers = concat(numbers,char.substr(email,#pos,1)).
end loop.
exe.

*4. Convert string to numeric variable.
<\/strong>
alter type numbers(f1.0).<\/div>\n\n","protected":false},"excerpt":{"rendered":"

The SPSS CHAR.INDEX function returns the position of the first occurrence of a given expression within a string. If this expression does not occur in the string, it returns a zero.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[70],"tags":[],"class_list":["post-340","post","type-post","status-publish","format-standard","hentry","category-spss-string-functions"],"_links":{"self":[{"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/posts\/340","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/comments?post=340"}],"version-history":[{"count":0,"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/posts\/340\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/media?parent=340"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/categories?post=340"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.spss-tutorials.com\/wp-json\/wp\/v2\/tags?post=340"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}