Transform snake_case to camelCase

Question

I want to convert db columns such as is_deleted or product_code which consist of xx_xx to java-style names: isDeleted or productCode. I wonder if there is a way to improve my following code, using regex or such things.

def getJavaName(column): 
 words = column.split('_') 
 first = words[0] 
 return first + ''.join((w.capitalize() for w in words[1:])) 

• user69264: Since this is under the code review section, I'll provide the answer I would in a real code review. Don't do it at all. Doing a refactoring of naming in this way has a fair chance of introducing bugs with no improvement in functionality. AKA: If it ain't broke don't fix it. Spend the time you save working on new features or fixing real problems.
• Mark Soul: @user69264 Thanks for practical suggestions. Actually,I wrote this script replace an Eclipse plugin used in my work, also for purpose——leaning python :)
• mckenzm: Actually this type of name refactoring has been going on for years in the Client-Server, SOA, and ETL spaces. It is not so much to rename columns or alter DDL, but to create mappings of the objects as structs and such. So if I am working in C, I want the naming conventions and familiar look and feel. This matters still as there is a lot of Java-DB2 going on. Not to mention Django.

Answer 1

You should remove the many trailing spaces.

You can replace slicing with unpacking and the double-brackets can be removed:

def getJavaName(column):
 first, *rest = column.split('_')
 return first + ''.join(word.capitalize() for word in rest)

Python uses snake_case, even if your DB columns don't, so you should be calling this get_java_name - although personally it's still better named snake_to_camel_case and the column parameter should be renamed to, say, name.

• JaDogg: I like the way you are doing the extraction. nice.
• Nizam Mohamed: first, *rest = column.split('_') doesn't work in Python 2.x.
• Mark Soul: @NizamMohamed you can use first, rest = column.split('')[0], column.spilt('')[1:] in Python 2.x
• Daniel Dror: Thanks for this, neat little trick for manipulating the result array

Answer 2

Using regex,

import re
def getJavaName(column):
 return re.sub('_.',lambda x: x.group()[1].upper(),column)

Answer 3

Consider writing this as a one-liner regular expression substitution instead.

import re
def get_java_name(column_name):
 return re.sub('_([a-z])', lambda match: match.group(1).upper(), column_name)

Since the function is Python code, it should still adhere to PEP 8 naming conventions — get_java_name() instead of getJavaName().

• Veedrac: This fails for non-ASCII identifiers. You might argue that it's bad practice anyway, though ;).