String building with regex

Question

So I am fairly new to python and am only self taught in this particular language, but I have hit a bit of a snag.

What I am trying to do is build a string that has with in it a digit that can be of any length or pattern. For example:

   "Data_image_%s.%d" %(myStr, r'[0-9]+') 
   # Well, this won't actually work since %d is expecting an integer,
   # but you get the idea.

When I do this I get back

Data_image_picture.[0-9]+.png

The ultimate objective is to create a string that reads like: Data_image_picture.1234567.png

Any thoughts on how I might go about correcting this?

Edit: What I am trying to do is take images off my companies website but the image url is dynamic depending on who and when the images are loaded to the browser. So the format is typically "data_image_Joe_session#id.png

Edit 2: I think I have been going about this problem the wrong way, I'll likely need to parse through the data to figure what string patterns I need, instead of creating a one size fits all string like I have been doing.

Thank you for your time and help

You wanna bulk create strings on that shape? Like from Data_image_picture.0.png to Data_image_picture.9223372036854775807.png ? — Savir
– Savir, Commented Dec 3, 2014 at 22:41
What I am trying to do is take images off my companies website but the image url is dynamic depending on who and when the images are load to the browser. so the format is typically "data_image_Joe_session#id.png — Riv3r
– Riv3r, Commented Dec 3, 2014 at 22:48
Do you know that id before trying to generate the Data_image_picture...blahblah? I mean... Are you gonna know what number you need to add to it? If that's the case, what @TanveerAlam or @Hackaholic posted below should be good. — Savir
– Savir, Commented Dec 3, 2014 at 22:50

Hart Simha · Accepted Answer · 2014-12-03 22:42:43Z

1

Regular expressions are used for matching, not for building strings or building random numbers.

To build a string with a random number between 0 and 9999999 you could do something like:

from random import random

myStr = "Data_image_picture." + str(int(random()*10000000)) + ".png"

answered Dec 3, 2014 at 22:42

Hart Simha

9028 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Tanveer Alam · Accepted Answer · 2014-12-03 23:15:21Z

1

%d is used as a placeholder for numeric or decimal values.

They are format specifiers. They are used when you want to include the value of your Python expressions into strings, with a specific format enforced.

So %d accepts integer but place it inside string.

>>> image_name = "picture"
>>> image_number = 1234567
>>> "Data_image_%s.%d.jpg"%(image_name,image_number)
'Data_image_picture.1234567.jpg'
#OR
>>> "Data_image_{}.{}.jpg".format(image_name,image_number)
'Data_image_picture.1234567.jpg'

You can check the type of the number that is formated inside string:

>>> type(image_number)
<type 'int'>

You can take number of any lenght.

>>> image_number = 123456789234567
>>> image_name = "picture"
>>> "Data_image_%s.%d.jpg"%(image_name,image_number)
'Data_image_picture.123456789234567.jpg'
>>> type(image_number)
<type 'long'>

This is in Python 2 but in Python 3 integer can hold up long numbers.

In Python3:

image_number = 123456789234567
image_name = "picture"
print ("Data_image_%s.%d.jpg"%(image_name,image_number))
print (type(image_number))

Results :

Data_image_picture.123456789234567.jpg
<class 'int'>

edited Dec 3, 2014 at 23:15

answered Dec 3, 2014 at 22:48

Tanveer Alam

5,2754 gold badges24 silver badges44 bronze badges

2 Comments

Riv3r Over a year ago

I think I have been going about this problem the wrong way, I'll likely need to parse through the data to figure what string patterns I need.

Tanveer Alam Over a year ago

@Riv3r Yes i think you just got confused because you thought you are trying to include integer with string.

Collectives™ on Stack Overflow

String building with regex

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related