Print letters in specific pattern in Python

Question

I have the follwing string and I split it:

>>> st = '%2g%k%3p' >>> l = filter(None, st.split('%')) >>> print l ['2g', 'k', '3p'] 

Now I want to print the g letter two times, the k letter one time and the p letter three times:

ggkppp 

How is it possible?

Answer 1

You could use generator with isdigit() to check wheter your first symbol is digit or not and then return following string with appropriate count. Then you could use join to get your output:

''.join(i[1:]*int(i[0]) if i[0].isdigit() else i for i in l) 

Demonstration:

In [70]: [i[1:]*int(i[0]) if i[0].isdigit() else i for i in l ] Out[70]: ['gg', 'k', 'ppp']  In [71]: ''.join(i[1:]*int(i[0]) if i[0].isdigit() else i for i in l) Out[71]: 'ggkppp' 

EDIT

Using re module when first number is with several digits:

''.join(re.search('(\d+)(\w+)', i).group(2)*int(re.search('(\d+)(\w+)', i).group(1)) if re.search('(\d+)(\w+)', i) else i for i in l) 

Example:

In [144]: l = ['12g', '2kd', 'h', '3p']  In [145]: ''.join(re.search('(\d+)(\w+)', i).group(2)*int(re.search('(\d+)(\w+)', i).group(1)) if re.search('(\d+)(\w+)', i) else i for i in l) Out[145]: 'ggggggggggggkdkdhppp' 

EDIT2

For your input like:

st = '%2g_%3k%3p' 

You could replace _ with empty string and then add _ to the end if the work from list endswith the _ symbol:

st = '%2g_%3k%3p' l = list(filter(None, st.split('%'))) ''.join((re.search('(\d+)(\w+)', i).group(2)*int(re.search('(\d+)(\w+)', i).group(1))).replace("_", "") + '_' * i.endswith('_') if re.search('(\d+)(\w+)', i) else i for i in l) 

Output:

'gg_kkkppp' 

EDIT3

Solution without re module but with usual loops working for 2 digits. You could define functions:

def add_str(ind, st):     if not st.endswith('_'):         return st[ind:] * int(st[:ind])     else:         return st[ind:-1] * int(st[:ind]) + '_'  def collect(l):     final_str = ''     for i in l:         if i[0].isdigit():             if i[1].isdigit():                 final_str += add_str(2, i)             else:                 final_str += add_str(1, i)         else:             final_str += i     return final_str 

And then use them as:

l = ['12g_', '3k', '3p']  print(collect(l)) gggggggggggg_kkkppp