CODEWITHSUNDEEP
python
Mahendra
Mahendra

Reputation: 333

How do I add serial number by replacing character in string in Python?

oldName = "old_###"

now I want to convert all the "#" in to the serial number, for example, in this case oldName should be "old_001"

is there any possible Pythonic Way to do this?

Upvotes: 0

Views: 1150

Answers (4)

Mark Tolonen
Mark Tolonen

Reputation: 177685

If ### isn't a requirement:

print 'old_{:03d}'.format(1)

If you need ###, here's a way to compute the format string:

import re
name = "old_#####"
fmt = re.sub(r'#+',lambda m: r'{{:0{}d}}'.format(len(m.group(0))),name)
print name
print fmt
for i in range(5):
    print fmt.format(i)

Output

old_#####
old_{:05d}
old_00000
old_00001
old_00002
old_00003
old_00004

Upvotes: 1

spicavigo
spicavigo

Reputation: 4224

oldName = "old_{serial_number}"
oldName.format(serial_numer='001')

Of course, this assumes that you do not really have to use '#'.

Upvotes: 1

Constantinius
Constantinius

Reputation: 35059

Try it with string formatting:

number = 123
serial_number = "old_%03d" % number

Upvotes: 1

Feanor
Feanor

Reputation: 670

Couldn't you just do:

oldName.replace('###', '001')

Of course my assumption here is that you always have 3 '#' symbols.

Simple is the best way to go I say, if this works you won't need to use the re module.

Upvotes: 3

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