How to iterate over associative arrays in Bash

Question

Based on an associative array in a Bash script  I need to iterate over it to get the key and value      bin bash  declare -A array array foo  bar array bar  foo   I actually don t understand how to get the key while using a for-in loop

User · Answer

You can access the keys with    array       bash-4 0  echo     array      foo bar   Then  iterating over the key value pairs is easy   for i in     array      do   echo  key     i   echo  value     array  i   done

User · Answer

Welcome to input associative array 2 0      clear     echo  quot Welcome to input associative array 2 0   Spaces in keys and values now supported  quot      unset array     declare -A array     read -p  Enter number for array size    num     for    i 0  i  lt  num  i              do             echo -n  quot  pair      i 1     quot              read -p   Enter key    k             read -p           Enter value    v             echo  quot   quot              array  k   v         done     echo  quot   quot      echo  quot The keys are   quot     array         echo  quot The values are   quot    array         echo  quot   quot      echo  quot Key  lt - gt  Value quot      echo  quot ------------- quot      for i in  quot    array     quot   do echo  i  quot  lt - gt  quot    array  i    done     echo  quot   quot      echo  quot Thanks for using input associative array 2 0  quot   Output  Welcome to input associative array 2 0   Spaces in keys and values now supported  Enter number for array size  4  pair 1  Enter key  Key Number 1          Enter value  Value 1   pair 2  Enter key  Key Two          Enter value  Value2   pair 3  Enter key  Key3          Enter value  Val3   pair 4  Enter key  Key4          Enter value  Value4   The keys are   Key4 Key3 Key Number 1 Key Two The values are   Value4 Val3 Value 1 Value2  Key  lt - gt  Value ------------- Key4  lt - gt  Value4 Key3  lt - gt  Val3 Key Number 1  lt - gt  Value 1 Key Two  lt - gt  Value2  Thanks for using input associative array 2 0    Input associative array 1 0  keys and values that contain spaces are not supported      clear     echo  quot Welcome to input associative array   written by mO extraordinaire   quot      unset array     declare -A array     read -p  Enter number for array size    num     for    i 0  i  lt  num  i              do             read -p  Enter key and value separated by a space    k v             array  k   v         done     echo  quot   quot      echo  quot The keys are   quot     array         echo  quot The values are   quot    array         echo  quot   quot      echo  quot Key  lt - gt  Value quot      echo  quot ------------- quot      for i in    array      do echo  i  quot  lt - gt  quot    array  i    done     echo  quot   quot      echo  quot Thanks for using input associative array  quot   Output  Welcome to input associative array   written by mO extraordinaire   Enter number for array size  10 Enter key and value separated by a space  a1 10 Enter key and value separated by a space  b2 20 Enter key and value separated by a space  c3 30 Enter key and value separated by a space  d4 40 Enter key and value separated by a space  e5 50 Enter key and value separated by a space  f6 60 Enter key and value separated by a space  g7 70 Enter key and value separated by a space  h8 80 Enter key and value separated by a space  i9 90 Enter key and value separated by a space  j10 100  The keys are   h8 a1 j10 g7 f6 e5 d4 c3 i9 b2 The values are   80 10 100 70 60 50 40 30 90 20  Key  lt - gt  Value ------------- h8  lt - gt  80 a1  lt - gt  10 j10  lt - gt  100 g7  lt - gt  70 f6  lt - gt  60 e5  lt - gt  50 d4  lt - gt  40 c3  lt - gt  30 i9  lt - gt  90 b2  lt - gt  20  Thanks for using input associative array

User · Answer

Use this higher order function to prevent the pyramid of doom  foreach       arr    declare -p  1     eval  declare -A f    arr         for i in    f      do  2   i     f  i     done     example      bar    echo   1 - gt   2       declare -A foo  flap    three four  foo  flop    one two    foreach foo bar flap - gt  three four flop - gt  one two

User · Answer

The keys are accessed using an exclamation point     array      the values are accessed using   array       You can iterate over the key value pairs like this   for i in     array      do   echo  key     i    echo  value    array  i    done   Note the use of quotes around the variable in the for statement  plus the use of   instead of     This is necessary in case any keys include spaces   The confusion in the other answer comes from the fact that your question includes  foo  and  bar  for both the keys and the values

User · Answer

declare -a arr echo  -------------------------------------  echo  Here another example with arr numeric  echo  -------------------------------------  arr   10 200 3000 40000 500000 60 700 8000 90000 100000    echo -e   n Elements in arr are  n   arr 0    n   arr 1    n   arr 2    n   arr 3    n   arr 4    n   arr 5    n   arr 6    n   arr 7    n   arr 8    n   arr 9     echo -e    n Total elements in arr are     arr      n   echo -e    n Total lenght of arr is      arr      n   for    i 0  i lt 10  i      do      echo  The value in position  i for arr is     arr i      done  for    j 0  j lt 10  j      do      echo  The length in element  j is    arr j    done  for z in     arr      do      echo  The key ID is  z  done

[bash] How to iterate over associative arrays in Bash

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