Inserting space before capital letter in attribute using QGIS field calculator?

Question

I have a field, and it has many words in it for every row and I want to insert a space before every capital letter except of the first one.

Example: I have something like this:

GeorgeJohnMike

or

George smithJohnMike

And I want to modified it some thing like this:

George John Mike

or

George smith John Mike

How can I do it using QGIS or in ArcGis?

Answer 1

FOR QGIS:

You can use below expressions:

replace((regexp_replace("YourField", '(?!^)([A-Z])', ' \\1')),'  ', ' ')

N.B. I am surprised that qgis does not support negative look behind though python 2.7 fully supports it.

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FOR ArcGIS:

Basically, this answer is equally applied for ArcGIS and QGIS. I will use regular expression to solve the problem

I would use below function in the arcmap field calculator:

import re
def spacer(text):
    return re.sub(r'([A-Z])',r" \1",text,re.MULTILINE).strip()

or below if there is a single space already before any capital letter in the passed text.

import re
def spacer(text):
    return re.sub(r'([A-Z])',r" \1",text,re.MULTILINE).strip().replace("  "," ")

Example:

Explanation:

I used re.sub(r'([A-Z])',r" \1",text,re.MULTILINE).strip() lets explain it.

re.sub just grabs all that matches ([A-Z]) from the input text and replaces it with the exactly that character but with leading space but it, thus, adds a leading space in the beginning of the line which is unwanted.So I used strip() function to remove unwanted leading and trailing spaces.

Explanation of the regular expression ([A-Z]): It grabs all single character capital letters.

Explanation of the regular expression r \1: Here r is just a formatting flag and in space+\1, \1 is called backreference which returns the character grabbed by the previous regular expression.So replacing text is the exact Capital letters that grabbed by the previous regex plus the leading space.

Answer 2

In the field calculator:

regexp_replace("FIELD",'\\B([A-Z])',' \\1')

For your example:

regexp_replace('GeorgeJohnMike','\\B([A-Z])',' \\1')

gives:

George John Mike

Answer 3

This works in QGIS:

 regexp_replace("field", '(?!^)(?=[A-Z])', ' ')

Short regex explanation:

• (?=[A-Z]) is a positive lookahead that tells the regex engine to stop before each capital letter
• (?!^) is a negative lookahead that excludes the beginning of the input string (thus avoiding to take into account the first character if it is a capital letter).

Answer 4

Not completely a GIS question, and you'll find better code that mine in SO, but here is a Python code that you could use in arcGIS field calculator.

def addSpace(word):
    outword=word[0]
    for letter in word[1:]:
        if letter.isupper():
            outword+=' ' + letter
        else:
            outword+= letter
    return outword

And if you like one liners:

(''.join([" " + letter if letter.isupper() else letter for letter in word])).lstrip()