python for increment inner loop

Question

How to increment the outer iterator from the inner loop    To be more precise     for i in range 0 6       print i     for j in range 0 5         i   i 2   I am getting  0 1 2 3 4 5     but I want 0 2 4  Above is the simpilfied idea what I want to acheive   Here is my Java code   str1  ababa  str2  aba  for int i  0  i  lt  str1 length  i      for int j  0  j  lt  str2 length  j           if str1 i j   str j             break         if  j   str2 length -1             i i str2 length

User · Answer

In python  for loops iterate over iterables  instead of incrementing a counter  so you have a couple choices   Using a skip flag like Artsiom recommended is one way to do it   Another option is to make a generator from your range and manually advance it by discarding an element using next     iGen    i for i in range 0  6   for i in iGen      print i     if not i   2          iGen next     But this isn t quite complete because next   might throw a StopIteration if it reaches the end of the range  so you have to add some logic to detect that and break out of the outer loop if that happens   In the end  I d probably go with aw4ully s solution with the while loops

User · Answer

It seems that you want to use step parameter of range function  From documentation      range start  stop   step   This is a versatile function to create   lists containing arithmetic progressions  It is most often used in for   loops  The arguments must be plain integers  If the step argument is   omitted  it defaults to 1  If the start argument is omitted  it   defaults to 0  The full form returns a list of plain integers  start    start   step  start   2   step        If step is positive  the last   element is the largest start   i   step less than stop  if step is   negative  the last element is the smallest start   i   step greater   than stop  step must not be zero  or else ValueError is raised     Example      gt  gt  gt  range 10   0  1  2  3  4  5  6  7  8  9    gt  gt  gt  range 1  11   1  2  3  4  5  6  7  8  9  10    gt  gt  gt  range 0  30  5   0  5  10  15  20  25    gt  gt  gt  range 0  10  3   0  3  6  9    gt  gt  gt  range 0  -10  -1   0  -1  -2  -3  -4  -5  -6  -7  -8  -9    gt  gt  gt  range 0       gt  gt  gt  range 1  0       In your case to get  0 2 4  you can use   range 0 6 2    OR in your case when is a var   idx   None for i in range len str1        if idx and i  lt  idx          continue     for j in range len str2            if str1 i j     str2 j               break     else          idx   i j

User · Answer

for a in range 1        for b in range 3           a   b 2         print a    As per your question  you want to iterate the outer loop with help of the inner loop    In outer loop  we are iterating the inner loop 1 time  In the inner loop  we are iterating the 3 digits which are in the multiple of 2  starting from 0   Output  0 2 4

User · Answer

I read all the above answers and those are actually good   look at this code   for i in range 1  4       print  Before change    i      i   20   changing i variable     print  After change    i    this line will always print 20   When we execute above code the output is like below   Before Change  1 After change  20 Before Change  2 After change  20 Before Change  3 After change  20   in python for loop is not trying to increase i value  for loop is just assign values to i which we gave  Using range 4  what we are doing is we give the values to for loop which need assign to the i   You can use while loop instead of for loop to do same thing what you want   i   0 while i  lt  6      print i      j   0     while j  lt  5          i    2   to increase  i  by 2   This will give   0 2 4   Thank you

User · Answer

You might just be better of using while loops rather than for loops for this  I translated your code directly from the java code   str1    ababa  str2    aba  i   0  while i  lt  len str1     j   0   while j  lt  len str2       if not str1 i j     str1 j         break     if j     len str2  -1         i    len str2      j  1     i  1

[python] python for increment inner loop

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