Find an element in a list of tuples

Question

I have a list  a   a    1 2   1 4   3 5   5 7     I need to find all the tuples for a particular number  say for 1 it will be  result     1 2   1 4     How do I do that

User · Accepted Answer

If you just want the first number to match you can do it like this    item for item in a if item 0     1    If you are just searching for tuples with 1 in them    item for item in a if 1 in item

User · Answer

There is actually a clever way to do this that is useful for any list of tuples where the size of each tuple is 2  you can convert your list into a single dictionary   For example   test      hi   1     there   2   test   dict test  print test  hi     prints 1

User · Answer

Or takewhile    addition to this  example of more values is shown      gt  gt  gt  a    1 2   1 4   3 5   5 7   0 2    gt  gt  gt  import itertools  gt  gt  gt  list itertools takewhile lambda x  x 0   1 a     1  2    1  4    gt  gt  gt     if unsorted  like    gt  gt  gt  a    1 2   3 5   1 4   5 7    gt  gt  gt  import itertools  gt  gt  gt  list itertools takewhile lambda x  x 0   1 sorted a key lambda x  x 0   1      1  2    1  4    gt  gt  gt

User · Answer

gt  gt  gt   i for i in a if 1 in i      1  2    1  4

User · Answer

for item in a     if 1 in item         print item

User · Answer

The filter function can also provide an interesting solution  result   list filter lambda x  x count 1   gt  0  a    which searches the tuples in the list a for any occurrences of 1  If the search is limited to the first element  the solution can be modified into  result   list filter lambda x  x 0     1  a

User · Answer

tup for tup in a if tup 0     1

User · Answer

if you want to search tuple for any number which is present in tuple then you can use  a    1 2   1 4   3 5   5 7   i 1 result    for j in a      if i in j          result append j   print result    You can also use if i  j 0  or i  j index  if you want to search a number in particular index

User · Answer

Read up on List Comprehensions     x y  for x  y in a if x     1     Also read up up generator functions and the yield statement   def filter value  someList  value        for x  y in someList          if x    value               yield x y  result  list  filter value  a  1

User · Answer

Using filter function       def get values iterables  key to find           return list filter lambda x key to find in x  iterables         a     1 2   1 4   3 5   5 7        get values a  1         1  2    1  4

[python] Find an element in a list of tuples

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