Dropping lists using pattern [duplicate]

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Matching a case when one element in a pair is Null

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I have the following list of lists.

 data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

I want to drop all the lists with 0 as the 3rd entry i.e. {m,n,0}. How can I do this?

asked 7 hours ago

Physics Moron

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marked as duplicate by Jason B., Henrik Schumacher, Kuba♦ list-manipulation
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This question already has an answer here:

Matching a case when one element in a pair is Null

2 answers

I have the following list of lists.

 data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

I want to drop all the lists with 0 as the 3rd entry i.e. {m,n,0}. How can I do this?

asked 7 hours ago

Physics Moron

253111

marked as duplicate by Jason B., Henrik Schumacher, Kuba♦ list-manipulation
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up vote
3
down vote

favorite

This question already has an answer here:

Matching a case when one element in a pair is Null

2 answers

I have the following list of lists.

 data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

I want to drop all the lists with 0 as the 3rd entry i.e. {m,n,0}. How can I do this?

asked 7 hours ago

Physics Moron

253111

This question already has an answer here:

Matching a case when one element in a pair is Null

2 answers

I have the following list of lists.

 data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

I want to drop all the lists with 0 as the 3rd entry i.e. {m,n,0}. How can I do this?

This question already has an answer here:

Matching a case when one element in a pair is Null

2 answers

list-manipulation pattern-matching

asked 7 hours ago

Physics Moron

253111

asked 7 hours ago

Physics Moron

253111

asked 7 hours ago

Physics Moron

253111

asked 7 hours ago

Physics Moron

253111

asked 7 hours ago

Physics Moron

253111

marked as duplicate by Jason B., Henrik Schumacher, Kuba♦ list-manipulation
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2 hours ago

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2 Answers
2

active

oldest

votes

up vote
4
down vote

accepted

Easy (but probably not the fastest) way:

DeleteCases[data, {_, _, 0}]

{{2, 0, 1}, {5, 0, 3}}

This might be a bit faster for longer lists as it entirely avoids pattern matching:

Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]

Here a speed test:

data = RandomInteger[{0, 5}, {1000000, 3}];

a = DeleteCases[data, {_, _, 0}]; // AbsoluteTiming // First

b = Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]; // 

   AbsoluteTiming // First

a == b

0.407339

0.027375

True

edited 5 hours ago

answered 7 hours ago

Henrik Schumacher

46.3k466133

add a comment |

up vote
1
down vote

Another way

data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

Pick[data, Unitize@data[[;; , 3]], 1]

{{2, 0, 1}, {5, 0, 3}}

And a timing comparison to DeleteCases

SeedRandom[1234]

Block[

 {data = RandomInteger[{0, 5}, {1000000, 3}], times, m1, m2},

 times = {

  AbsoluteTiming[m1 = DeleteCases[data, {__, 0}]][[1]],

  AbsoluteTiming[m2 = Pick[#, Unitize@#[[;; , 3]], 1] &@data][[1]]

 };

 {times, m1 == m2}

]

{{0.403632, 0.031339}, True}

answered 5 hours ago

That Gravity Guy

2,1011515

add a comment |

2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
4
down vote

accepted

Easy (but probably not the fastest) way:

DeleteCases[data, {_, _, 0}]

{{2, 0, 1}, {5, 0, 3}}

This might be a bit faster for longer lists as it entirely avoids pattern matching:

Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]

Here a speed test:

data = RandomInteger[{0, 5}, {1000000, 3}];

a = DeleteCases[data, {_, _, 0}]; // AbsoluteTiming // First

b = Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]; // 

   AbsoluteTiming // First

a == b

0.407339

0.027375

True

edited 5 hours ago

answered 7 hours ago

Henrik Schumacher

46.3k466133

add a comment |

up vote
4
down vote

accepted

Easy (but probably not the fastest) way:

DeleteCases[data, {_, _, 0}]

{{2, 0, 1}, {5, 0, 3}}

This might be a bit faster for longer lists as it entirely avoids pattern matching:

Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]

Here a speed test:

data = RandomInteger[{0, 5}, {1000000, 3}];

a = DeleteCases[data, {_, _, 0}]; // AbsoluteTiming // First

b = Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]; // 

   AbsoluteTiming // First

a == b

0.407339

0.027375

True

edited 5 hours ago

answered 7 hours ago

Henrik Schumacher

46.3k466133

add a comment |

up vote
4
down vote

accepted

Easy (but probably not the fastest) way:

DeleteCases[data, {_, _, 0}]

{{2, 0, 1}, {5, 0, 3}}

This might be a bit faster for longer lists as it entirely avoids pattern matching:

Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]

Here a speed test:

data = RandomInteger[{0, 5}, {1000000, 3}];

a = DeleteCases[data, {_, _, 0}]; // AbsoluteTiming // First

b = Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]; // 

   AbsoluteTiming // First

a == b

0.407339

0.027375

True

edited 5 hours ago

answered 7 hours ago

Henrik Schumacher

46.3k466133

Easy (but probably not the fastest) way:

DeleteCases[data, {_, _, 0}]

{{2, 0, 1}, {5, 0, 3}}

This might be a bit faster for longer lists as it entirely avoids pattern matching:

Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]

Here a speed test:

data = RandomInteger[{0, 5}, {1000000, 3}];

a = DeleteCases[data, {_, _, 0}]; // AbsoluteTiming // First

b = Delete[data, Partition[Random`Private`PositionsOf[data[[All, 3]], 0], 1]]; // 

   AbsoluteTiming // First

a == b

0.407339

0.027375

True

edited 5 hours ago

answered 7 hours ago

Henrik Schumacher

46.3k466133

edited 5 hours ago

answered 7 hours ago

Henrik Schumacher

46.3k466133

answered 7 hours ago

Henrik Schumacher

46.3k466133

answered 7 hours ago

Henrik Schumacher

46.3k466133

add a comment |

up vote
1
down vote

Another way

data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

Pick[data, Unitize@data[[;; , 3]], 1]

{{2, 0, 1}, {5, 0, 3}}

And a timing comparison to DeleteCases

SeedRandom[1234]

Block[

 {data = RandomInteger[{0, 5}, {1000000, 3}], times, m1, m2},

 times = {

  AbsoluteTiming[m1 = DeleteCases[data, {__, 0}]][[1]],

  AbsoluteTiming[m2 = Pick[#, Unitize@#[[;; , 3]], 1] &@data][[1]]

 };

 {times, m1 == m2}

]

{{0.403632, 0.031339}, True}

answered 5 hours ago

That Gravity Guy

2,1011515

add a comment |

up vote
1
down vote

Another way

data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

Pick[data, Unitize@data[[;; , 3]], 1]

{{2, 0, 1}, {5, 0, 3}}

And a timing comparison to DeleteCases

SeedRandom[1234]

Block[

 {data = RandomInteger[{0, 5}, {1000000, 3}], times, m1, m2},

 times = {

  AbsoluteTiming[m1 = DeleteCases[data, {__, 0}]][[1]],

  AbsoluteTiming[m2 = Pick[#, Unitize@#[[;; , 3]], 1] &@data][[1]]

 };

 {times, m1 == m2}

]

{{0.403632, 0.031339}, True}

answered 5 hours ago

That Gravity Guy

2,1011515

add a comment |

up vote
1
down vote

Another way

data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

Pick[data, Unitize@data[[;; , 3]], 1]

{{2, 0, 1}, {5, 0, 3}}

And a timing comparison to DeleteCases

SeedRandom[1234]

Block[

 {data = RandomInteger[{0, 5}, {1000000, 3}], times, m1, m2},

 times = {

  AbsoluteTiming[m1 = DeleteCases[data, {__, 0}]][[1]],

  AbsoluteTiming[m2 = Pick[#, Unitize@#[[;; , 3]], 1] &@data][[1]]

 };

 {times, m1 == m2}

]

{{0.403632, 0.031339}, True}

answered 5 hours ago

That Gravity Guy

2,1011515

Another way

data = {{0, 0, 0}, {1, 0, 0}, {2, 0, 1}, {3, 0, 0}, {4, 0, 0}, {5, 0, 3}}

Pick[data, Unitize@data[[;; , 3]], 1]

{{2, 0, 1}, {5, 0, 3}}

And a timing comparison to DeleteCases

SeedRandom[1234]

Block[

 {data = RandomInteger[{0, 5}, {1000000, 3}], times, m1, m2},

 times = {

  AbsoluteTiming[m1 = DeleteCases[data, {__, 0}]][[1]],

  AbsoluteTiming[m2 = Pick[#, Unitize@#[[;; , 3]], 1] &@data][[1]]

 };

 {times, m1 == m2}

]

{{0.403632, 0.031339}, True}

answered 5 hours ago

That Gravity Guy

2,1011515

answered 5 hours ago

That Gravity Guy

2,1011515

answered 5 hours ago

That Gravity Guy

2,1011515

answered 5 hours ago

That Gravity Guy

2,1011515

add a comment |

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