#!/usr/bin/env python
# coding: utf-8

# In[1]:


t = 'haystack needle haystack' # "text" - thing we search in
p = 'needle' # "pattern" - thing we search for


# In[2]:


def naive(p, t):
    assert len(p) <= len(t)  # assume text at least as long as pattern
    occurrences = []
    for i in range(len(t)-len(p)+1):  # for each alignment of p to t
        match = True  # assume we match until proven wrong
        for j in range(len(p)):  # for each position of p
            if t[i+j] != p[j]:
                match = False  # at least 1 char mismatches
                break
        if match:
            occurrences.append(i)
    return occurrences


# In[3]:


naive(p, t)


# In[4]:


t[9:9+len(p)]  # confirm it really occurs


# In[5]:


naive('needle', 'needleneedleneedle')