string replace in Python

Question

Want to find an elegant way to replace xxxxx part dynamically with an array of values (xxxxx is more like a template placeholder for real string values). For example, if the array is ["foo","goo","zoo"], I want to generate 3 dynamic strings

a="hello values: [xxxxx], have a good day"

Dynamic string expected,

"hello values: [foo], have a good day"
"hello values: [goo], have a good day"
"hello values: [zoo], have a good day"

thanks in advance, Lin

• Padraic Cunningham: Why do you have xxxxx?
• Lin Ma: @PadraicCunningham, just an example of placeholder. :)

Answer 1

The perfect use for map() even though list comprehensions are the newer, more idiomatic way to do it.

>>> a = "hello values: [{}]"
>>> names = ["foo", "goo", "zoo"]
>>> map(a.format, names)
['hello values: [foo]', 
 'hello values: [goo]', 
 'hello values: [zoo]']

• Tom Myddeltyn: This is the best Pythonic answer. You could also do [a.format(name) for name in names] instead of the map

Answer 2

use string replace function.

a.replace("xxxxxx", "foo")

for a list:

src_name = ["foo", "goo", "zoo"]
a = "hello values: [xxxxx], have a good day"
result = (a.replace("xxxxx", d) for d in src_name)
for i in result:
 print (i)

output:

hello values: [foo], have a good day
hello values: [goo], have a good day
hello values: [zoo], have a good day

• Lin Ma: Thanks for the help Mrunmoy, vote up and mark your reply as answer.

Answer 3

arr=["foo","goo","zoo"]
a="hello values: [xxxxx], have a good day"
for el in arr:
 print(a.replace("xxxxx",el))

Answer 4

The replace function is what you're looking for :

a.replace('xxxxx','stringtoreplace')

if you want to go through the array then :

for str in stringarray:
 print(a.replace('xxxxx',str))

Answer 5

My first intension is:

sentence = "hello values: [xxxxx], have a good day"
names = ["foo", "goo", "zoo"]
sentences = [sentence.replace("xxxxx", name) for name in names]

But I have a bad smell about your application ... it's a uncommon question.

Answer 6

I will loop through the array and perform regular expression on it.

Looking for a pattern occurence of "[xxxxx]" and replacing that with whatever the array value is.

You can also just simply replace xxx with the array value but that can be unreliable anchoring to [xxx] is much safer as that is stricter.

Python's regular expression API. https://docs.python.org/2/library/re.html

• Samuel Toh: Thanks. Vote up on the question too because I don't see how this is a troll question, which have already received -2 response. Everyone start somewhere, especially topic on string manipulation.